change release notes file name to use git repo name

[rishabh6788]

Description

In release notes generate workflow change the final filename to use git repo name instead of component name from manifest and set product name to OpenSearch for all plugins including dashboards plugins.

Issues Resolved

List any issues this PR will resolve, e.g. Closes [...].

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.57%. Comparing base (d8eccff) to head (654ba56).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5750   +/-   ##
=======================================
  Coverage   96.57%   96.57%           
=======================================
  Files         405      405           
  Lines       18506    18506           
=======================================
  Hits        17872    17872           
  Misses        634      634           

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