Reduce complexity of maintaining the Cocoa SDK plugin dependency

[tustanivsky]

Building sentry-cocoa is currently part of the UE plugin CI workflow. In case of significant changes, regular updates of the corresponding submodule require additional effort to fix the existing build scripts for iOS and Mac.

There are a few options to consider that can help to reduce the complexity of maintaining Cocoa SDK dependency:

• Download the required sentry-cocoa binaries from its GitHub release page (example of how this was done in Unity)
• Reuse the existing build-xcframework.sh script which sentry-cocoa relies on itself. Its current version is not optimized for Unreal (i.e. UE doesn't support Mac Catalyst or iPhone simulator) however it should be possible to introduce an extra parameter that will reduce build times and allow to skip unnecessary steps.