Add custom trigger for GHA workflows

[larohra]

Add custom trigger for GHA workflows

https://docs.github.com/en/actions/managing-workflow-runs/manually-running-a-workflow

[codecov]

Codecov Report

Merging #2214 (f7d9c09) into develop (5a13140) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #2214      +/-   ##
===========================================
- Coverage    70.55%   70.52%   -0.03%     
===========================================
  Files           96       96              
  Lines        13574    13574              
  Branches      1918     1918              
===========================================
- Hits          9577     9573       -4     
- Misses        3586     3589       +3     
- Partials       411      412       +1     

Impacted Files	Coverage Δ
azurelinuxagent/common/event.py	85.29% <0.00%> (-0.68%)	⬇️
azurelinuxagent/ga/exthandlers.py	86.73% <0.00%> (-0.09%)	⬇️

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