Add fallback when a there is no preview for a version

[artonge]

Fix#37067

Before (Chrome)	Before (Firefox)	After

@nextcloud/designers Unsure about the new icon. Do you prefer to go with the "After" version, or the "Firefox" one?
No icon could be confusing because the user might think that the file is empty, even though it might not.

[szaimen]

One small suggestion, apart from that tested and works and LGTM!

[artonge]

/backport to stable27

[artonge]

/backport to stable26

[artonge]

/backport to stable25

[nimishavijay]

Good call! The "After" version definitely looks better as you said, and agreed with @szaimen that it can be a lighter color :)

[artonge]

/compile amend /

[backportbot-nextcloud]

The backport to stable27 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable27
git pull origin/stable27
# Create the new backport branch
git checkout -b fix/foo-stable27
# Cherry pick the change from the commit sha1 of the change against the default branch# This might cause conflicts. Resolve them.
git cherry-pick abc123
# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable27

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport

[backportbot-nextcloud]

The backport to stable26 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable26
git pull origin/stable26
# Create the new backport branch
git checkout -b fix/foo-stable26
# Cherry pick the change from the commit sha1 of the change against the default branch# This might cause conflicts. Resolve them.
git cherry-pick abc123
# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable26

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport

[backportbot-nextcloud]

The backport to stable25 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable25
git pull origin/stable25
# Create the new backport branch
git checkout -b fix/foo-stable25
# Cherry pick the change from the commit sha1 of the change against the default branch# This might cause conflicts. Resolve them.
git cherry-pick abc123
# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable25

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport

[artonge]

/backport to stable25

[backportbot-nextcloud]

The backport to stable25 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable25
git pull origin/stable25
# Create the new backport branch
git checkout -b fix/foo-stable25
# Cherry pick the change from the commit sha1 of the change against the default branch# This might cause conflicts. Resolve them.
git cherry-pick abc123
# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable25

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport

[solracsf]

/backport to stable27

[solracsf]

/backport to stable26

[solracsf]

/backport to stable25

[backportbot-nextcloud]

The backport to stable26 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable26
git pull origin/stable26
# Create the new backport branch
git checkout -b fix/foo-stable26
# Cherry pick the change from the commit sha1 of the change against the default branch# This might cause conflicts. Resolve them.
git cherry-pick abc123
# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable26

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport

[backportbot-nextcloud]

The backport to stable25 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable25
git pull origin/stable25
# Create the new backport branch
git checkout -b fix/foo-stable25
# Cherry pick the change from the commit sha1 of the change against the default branch# This might cause conflicts. Resolve them.
git cherry-pick abc123
# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable25

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport

[backportbot-nextcloud]

The backport to stable27 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable27
git pull origin/stable27
# Create the new backport branch
git checkout -b fix/foo-stable27
# Cherry pick the change from the commit sha1 of the change against the default branch# This might cause conflicts. Resolve them.
git cherry-pick abc123
# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable27

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport

[solracsf]

Must be backported manually if needed, it seems 😞