fix: Rename internal SetupLogging to SetupUnityLogging

[bitsandfoxes]

This PR renames the internal extension-method SetupLogging to SetupUnityLogging on the SentryUnityOptions.

Context

With getsentry/sentry-dotnet#4026 and release 5.5.0 the Sentry .NET SDK made its internals visible to the Unity SDK. This causes the extension method to get skipped and instead of

sentry-unity/src/Sentry.Unity/SentryUnityOptionsExtensions.cs

Line 50 in 3e02634

internal static void SetupLogging(this SentryUnityOptions options)

the actual SetupLogging on the SentryOptions gets called, creating a ConsoleLogger instead.

#skip-changelog