feat: install Cocoapods by default in all projects

[szymonrybczak]

Summary

In #2116 we introduced opt-in way to install Cocoapods in run-ios commands, this PR changes that to be opt-out.

Test Plan

With empty react-native.config.js Cocoapods should still install.

Checklist

• Documentation is up to date.
• Follows commit message convention described in CONTRIBUTING.md.
• For functional changes, my test plan has linked these CLI changes into a local react-native checkout (instructions).

[thymikee]

All good! We should wait for the 0.79 cut to merge this, right?

[cipolleschi]

These changes will go "live" when we cut 0.79, but they are already in main.

I think you can merge this on main already... Until we cut the next release of the CLI, they won't be available to our users, no?

[szymonrybczak]

Until we cut the next release of the CLI, they won't be available to our users, no?

Yes, that's right.