fix: Removed build guid from Release

[bitsandfoxes]

Problem statement:
The build GUID is not available during build. So the release we set in the native SDKs during build time does not match the release during runtime.

I tried looking into retrieving the build GUID during the build process from BuildReport.BuidSummary.guid but that one does not seem to match Application.buildGuid of the app?

[github-actions]

	Fails
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## Unreleased

- Removed build guid from `Release` ([#1127](https://github.com/getsentry/sentry-unity/pull/1127))

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