Skip intermediate python wheels on pull request trigger

[Abacn]

Please add a meaningful description for your change here

These jobs run on GitHub hosted runner, and currently experiencing HTTP 429. Reduce the number of parallel jobs by half.

Also only run on push trigger on relevant code changes.

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[gemini-code-assist]

Note

Gemini is unable to generate a summary for this pull request due to the file types involved not being currently supported.

[Abacn]

R: @Amar3tto @tvalentyn

[github-actions]

Stopping reviewer notifications for this pull request: review requested by someone other than the bot, ceding control. If you'd like to restart, comment assign set of reviewers

[tvalentyn]

Thanks, @Abacn !