Improved issues comments pipeline

[bsekachev]

Motivation and context

• The latest comment shown in the sidebar
• Added ability to copy comments content
• Fixed some inconvenient behavior when canvas fit/moved or context menu for a shape opened when user acts on issue dialog
• Fixed blur effect appearing in some cases by changing css rules

How has this been tested?

Checklist

• I submit my changes into the develop branch
• I have added a description of my changes into the CHANGELOG file
• I have updated the documentation accordingly
• I have added tests to cover my changes
• I have linked related issues (see GitHub docs)
• I have increased versions of npm packages if it is necessary
  (cvat-canvas,
  cvat-core,
  cvat-data and
  cvat-ui)

License

• I submit my code changes under the same MIT License that covers the project.
  Feel free to contact the maintainers if that's a concern.

[codecov]

Codecov Report

Merging #6937 (d649d1c) into develop (0be063e) will increase coverage by 0.02%.
Report is 4 commits behind head on develop.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop    #6937      +/-   ##
===========================================
+ Coverage    82.59%   82.62%   +0.02%     
===========================================
  Files          360      360              
  Lines        38868    38867       -1     
  Branches      3544     3544              
===========================================
+ Hits         32104    32113       +9     
+ Misses        6764     6754      -10     

Components	Coverage Δ
cvat-ui	77.66% <100.00%> (+0.03%)	⬆️
cvat-server	87.15% <ø> (+0.01%)	⬆️

[klakhov]

What do you think about adding a colon after username like that: