Upgrading workflows to use gradle setup action

[jamonkko]

Summary

Upgrade workflows to use gradle setup-action v4 https://github.com/gradle/actions/tree/main?tab=readme-ov-file#the-setup-gradle-action

Basically just having this

- name: Setup Gradle
  uses: gradle/actions/setup-gradle@v4

and removing:

• usage gradle/wrapper-validation-action@v1. The setup-action@v4 will run internally wrapper validation.
• custom gradle cache tasks since setup-action@v4 will take care of gradle related caching and it is enabled by default when using it

Also would it make sense to update these quick start workflows to use setup-gradle@v4 since the current old gradle-validation action gets now copied to any project created using the template https://github.com/touchlab/KMMBridgeSPMQuickStart/tree/main/.github/workflows

I did not make ready PR since not sure if you are ok with these?

[kpgalligan]

I knew this was mentioned somewhere, but didn't look here. We just updated the samples, so I'll see about getting this in there rather than the current workflows.