Invalide temporary ID should probably not fail PR creation

[dsyme]

This workflow: https://github.com/fsprojects/FSharp.Data/actions/runs/23832103853/job/69469485819#step:9:314

Error: ✗ Message 2 (create_pull_request) failed: Invalid temporary_id format: 'aw_pr_testfix'. Temporary IDs must be in format 'aw_' followed by 3 to 12 alphanumeric characters (A-Za-z0-9). Example: 'aw_abc' or 'aw_Test123'

This failed the whole "create_pull_request" and the whole workflow. This doesn't seem right as it's a minor problem in the preparation of the results.

@pelikhan We should make this a warning?

[pelikhan]

yes warning.

[pelikhan]

Be more lenient on invalid temp ids. Support _ in identifier.