Fix bio.tools workflows

[anitamnd]

biotools-pr-validator:

• refactor the PR validator workflow to improve concurrency handling (group runs by PR and cancel in progress)
• ensure the workflow runs only when triggered by the biotools-bot user

biotools-gh2biotools:

• refactor run gh2biotools.py script step and fix script execution
• move protected fields validation to a script in utils repository (PR Refactor bio.tools sync: add protected fields validation, BioToolsClient, and improve update logic utils#51)

[anitamnd]

@hmenager, can you check if protected fields validation should be skipped for bioconductor-to-biotools imports?