refactor: Streamline leaving and clearing conversation

[atomrc]

Description

Avoid mixing clearing and leaving conversation. Make the code much leaner and avoid confusion between those 2 actions

previously: leaveConversation and clearConversation could both do leaving AND clearing the conversation.
now: leaveConversation only does leaving and clearConversation only does clearing

Checklist

• 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;

[codecov]

Codecov Report

Merging #15965 (5581021) into dev (c2bd51f) will increase coverage by 0.00%.
Report is 1 commits behind head on dev.
The diff coverage is 4.34%.

@@           Coverage Diff           @@
##              dev   #15965   +/-   ##
=======================================
  Coverage   44.28%   44.29%           
=======================================
  Files         683      683           
  Lines       22918    22916    -2     
  Branches     5213     5211    -2     
=======================================
  Hits        10150    10150           
+ Misses      11467    11465    -2     
  Partials     1301     1301           

[PatrykBuniX]

Nice, I agree it was hard to follow the flow with the previous structure 👌