fix(sharing): Add isTrustedServer flag to lookup results

[nfebe]

When show_federated_shares_to_trusted_servers_as_internal is enabled, lookup server results were being filtered out because they lacked the isTrustedServer flag. This adds the flag to lookup results by:

• Injecting TrustedServers service into LookupPlugin
• Adding server and isTrustedServer fields to each lookup result
• Updating tests to reflect new structure

This ensures lookup results from trusted servers appear in internal sharing while non-trusted servers are correctly filtered out.

[nfebe]

/backport to 32

[nfebe]

/backport to 31

[maximelehericy]

tested and works as expected:
results from the lookup server are shown in the sharing propositions.

[backportbot]

The backport to 31 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout 31
git pull origin 31
# Create the new backport branch
git checkout -b backport/56501/31
# Cherry pick the change from the commit sha1 of the change against the default branch# This might cause conflicts, resolve them
git cherry-pick 40246d9a
# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/56501/31

Error: Failed to clone repository: Failed to create working tree: Preparing worktree (new branch 'backport/56501/31')
fatal: not a valid object name: 'origin/31'

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Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.

[backportbot]

The backport to 32 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout 32
git pull origin 32
# Create the new backport branch
git checkout -b backport/56501/32
# Cherry pick the change from the commit sha1 of the change against the default branch# This might cause conflicts, resolve them
git cherry-pick 40246d9a
# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/56501/32

Error: Failed to clone repository: Failed to create working tree: Preparing worktree (new branch 'backport/56501/32')
fatal: not a valid object name: 'origin/32'

---

Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.