feat: update group avatars, select from 15 options [WPB-15794]

[e-maad]

WPB-15794 [Web] Adjust group avatars (not channels) to be in line with channel mocks

Description

Updated group avatars, select from 15 options of colors set.

Screenshots/Screencast (for UI changes)

Conversation List

Calling header

Connection Requests

Checklist

• mentions the JIRA issue in the PR name (Ex. [WPB-XXXX])
• PR has been self reviewed by the author;
• Hard-to-understand areas of the code have been commented;
• If it is a core feature, unit tests have been added;

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud