Fix Enumeration Helper to avoid potential runtime errors with NET 7

[utpilla]

Fix the reflection logic in EnumerationHelper to avoid potential runtime errors with NET 7.

The issue is with the enumerating over tags of ActivityLinks and ActivityEvents as the name of the internal type that the reflection code relies on is changed in NET 7. Currently, none of the projects in the contrib repo are affected as none of them enumerate over tags of ActivityLinks and ActivityEvents.

Refer to the issue and the fix in the main repo for the same:

• ALERT: Possible app crash for OpenTelemetry .NET versions 1.3.0 and prior opentelemetry-dotnet#3629
• [1.3.0 patch] Fix enumerator reflection when using DS7 version opentelemetry-dotnet#3605