refactor onPluginUpdate, added tests for it

[NamitBhutani]

What kind of change does this PR introduce?
refactor, tests

Issue Number:

Fixes #1923

Did you add tests for your changes?

Yes

Does this PR introduce a breaking change?

No

Have you read the contributing guide?

Yes

[github-actions]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.24%. Comparing base (36b3f5d) to head (85b64ab).
Report is 1 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2114      +/-   ##
===========================================
+ Coverage    96.17%   96.24%   +0.07%     
===========================================
  Files          333      333              
  Lines        22536    22536              
  Branches      1949     1987      +38     
===========================================
+ Hits         21673    21690      +17     
+ Misses         854      839      -15     
+ Partials         9        7       -2     

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[Cioppolo14]

@NamitBhutani You should have a specific issue to link to, not the parent issue. Can you please link that?

[NamitBhutani]

@NamitBhutani You should have a specific issue to link to, not the parent issue. Can you please link that?

Done! Sorry for the oversight.

[Cioppolo14]

@DMills27 @SiddheshKukade Can you review this PR?