Fix GHAs (convert-proto, cleanup-release)

[karenyrx]

Address the following 2 problems:

Problem 1

• Problem: The convert-proto GHA should not create a new PR in this repository everytime someone makes a PR to this repo, since these autogenerated PRs will never be merged and are a temporary artifact.

• Fix: A better way is to generate the artifact and expose it in the GHA. Thus modify the GHA to do so.

• Test Plan: Tested that this GHA run has this step:

shows:

Artifact download URL: https://github.com/opensearch-project/opensearch-protobufs/actions/runs/22427514436/artifacts/5666184494

which after downloading looks like this:

Problem 2

• Problem:cleanup-release GHA recently started failing because a GHA we were depending on has been deleted (Error: Unable to resolve action nguyenvukhang/semver-increment, repository not found, as witnessed in this workflow run).
• Fix: Remove that dependency and write a simple bash script to increment the minor version ourselves.
• Test Plan: Tested the bash script locally will increment the version.properties from 1.3.0 to 1.4.0. Plan to run the manually trigger the GHA after this PR is merged to main.

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 91.86%. Comparing base (9fd701d) to head (dfecae5).
⚠️ Report is 8 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #403   +/-   ##
=======================================
  Coverage   91.86%   91.86%           
=======================================
  Files          15       15           
  Lines        1364     1364           
  Branches      369      377    +8     
=======================================
  Hits         1253     1253           
+ Misses        110      105    -5     
- Partials        1        6    +5     

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[karenyrx]

Remove this change before merging - this is for testing only