Fix flaky ClaimTypesConst tests by serializing the Security test assembly (#171)

ClaimTypesConstTests.Configure_AppliesCustomValues intermittently failed on CI
(seeing the default role claim URI instead of the configured "roles"). Root
cause is a cross-class race on the process-wide mutable static ClaimTypesConst:
both ClaimTypesConstTests and ClaimsIdentityExtensionsTests call the internal
Reset() in ctor/Dispose, and under xUnit's default per-class parallelism a
parallel Reset() can null the options mid-test so a later property read rebuilds
defaults.

Disable test parallelization for RCommon.Security.Tests so the shared static
state is deterministic. Pre-existing flake, unrelated to the 3.1.1 changes; it
blocked the release CI run.

Co-authored-by: jasonmwebb-lv <jason.webb@leadventure.com>

Author: JasonMWebb

Tests/RCommon.Security.Tests/AssemblyInfo.cs

@@ -0,0 +1,10 @@
+using Xunit;
+
+// Several test classes in this assembly exercise ClaimTypesConst, which is a process-wide mutable
+// static (configure-once-at-startup). ClaimTypesConstTests and ClaimsIdentityExtensionsTests both
+// call the internal ClaimTypesConst.Reset() in their constructor/Dispose for isolation. Under xUnit's
+// default per-class parallelism these classes race on that global: a parallel Reset() can null the
+// options mid-test, so a subsequent property read rebuilds defaults and a configured value (e.g. a
+// custom Role) reverts to the default claim URI. Serialize the assembly's tests to make the shared
+// static state deterministic.
+[assembly: CollectionBehavior(DisableTestParallelization = true)]