Add System.StringComparer to sandbox

Fixes #6081

RELEASE-NOTES.md

@@ -40,7 +40,7 @@ END TEMPLATE-->
 ### New features
 
 * If a sandbox error is caused by a compiler-generated method, the engine will now attempt to point out which using code is responsible.
-* Added `OrderedDictionary<TKey, TValue>` to the sandbox whitelist.
+* Added `OrderedDictionary<TKey, TValue>` and `System.StringComparer` to the sandbox whitelist.
 
 ### Bugfixes
 

Robust.Shared/ContentPack/Sandbox.yml

@@ -1463,6 +1463,7 @@ Types:
       - "void .ctor(char[], int, int)"
       - "void .ctor(System.ReadOnlySpan`1<char>)"
       - "void CopyTo(int, char[], int, int)"
+    StringComparer: { All: True }
     StringComparison: { } # Enum
     StringSplitOptions: { } # Enum
     TimeOnly: { All: True }