ci: reduce actions trigger scope for push to main only

[eiri]

PR summary

Currently our actions triggered twice on each PR - once for PR itself another one for push. We can reduce waste to only triggering push for main and keeping PR check.

PR Checklist

Please make sure that your PR fulfills the following requirements:

• [x] The commit message follows the Angular Commit Message Guidelines.
• [ ] Tests for the changes have been added (for bug fixes / features)
• [ ] Docs have been added / updated (for bug fixes / features)

PR Type

• [ ] Bugfix
• [ ] Feature
• [ ] Code style update (formatting, local variables)
• [ ] Refactoring (no functional changes, no api changes)
• [ ] New tests
• [x] Build/CI related changes
• [ ] Documentation content changes
• [ ] Other (please describe)

What is the current behavior?

What is the new behavior?

Does this PR introduce a breaking change?

• [ ] Yes
• [x] No

Other information