ci: don't run tests for release-please PRs

[DmitriyLewen]

Description

Release please PRs contain information only about created changes and don't affect source code.
To avoid running tests after every commit to main branch - we need to disable tests workflow for these PRs.

Checklist

• I've read the guidelines for contributing to this repository.
• I've followed the conventions in the PR title.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
• I've included a "before" and "after" example to the description (if the PR is a user interface change).