Run pre-commit via GitHub Actions

[IshaanDesai]

This PR does the following things:

1. Removes the Action to check formatting via clang-format, because it is now checked by directly running pre-commit. This increases maintainability as the clang-format version is now defined at only one place, the pre-commit config file.
2. Runs pre-commit via an Action, which checks formatting and also other things that are included in the pre-commit checks
3. The Ubuntu build Action now runs only once in a pull request to the main or develop branches. Earlier there used to always be two runs per push via a pull request.

[MakisH]

Makes sense to me, thanks for tidying up!