Merge branch 'get-last-active-span-optimization' of https://github.com/getsentry/sentry-dotnet into get-last-active-span-optimization

Author: jamescrosswell

CHANGELOG.md

@@ -8,6 +8,7 @@
 - Added distributed tracing without performance for Azure Function Workers ([#2630](https://github.com/getsentry/sentry-dotnet/pull/2630))
 - The SDK now provides and overload of `ContinueTrace` that accepts headers as `string` ([#2601](https://github.com/getsentry/sentry-dotnet/pull/2601))
 - Sentry tracing middleware now gets configured automatically ([#2602](https://github.com/getsentry/sentry-dotnet/pull/2602))
+- Added memory optimisations for GetLastActiveSpan ([#2642](https://github.com/getsentry/sentry-dotnet/pull/2642))
 
 ### Fixes