Reply button for thread view

[sosnovsky]

This PR adds reply button to thread view and fixes expand/close button color.

close#936
close#940

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Tests(delete all except exactly one):

• Tests will be added later - ui test for tapping the reply icon #937

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To be filled by reviewers

I have reviewed that this PR... (tick whichever items you personally focused on during this review):

• addresses the issue it closes (if any)
• code is readable and understandable
• is accompanied with tests, or tests are not needed
• is free of vulnerabilities
• is documented clearly and usefully, or doesn't need documentation

[tomholub]

Code looks good. Thanks! Will test.

[tomholub]

This name is much better - thank you!

[tomholub]

Works well. Maybe we should move the reply icon a tiny bit further from the chevron icon? Seem like they are a bit too close together. For spacing, can follow the space between the header icons which are comfortably apart. (people with fat fingers etc)

[sosnovsky]

Works well. Maybe we should move the reply icon a tiny bit further from the chevron icon? Seem like they are a bit too close together. For spacing, can follow the space between the header icons which are comfortably apart. (people with fat fingers etc)

Agree, looks quite close. I was also thinking about removing expand icon when message is expanded, so it'll be only reply button, as currently expand icon looks too repetitive, as for me. What do you think?