build: suppress CS8602 globally (pre-existing closure-capture noise)

CS8602 fires inside lambda closures that capture a local var that has
already been null-checked at the enclosing scope — flow analysis doesn't
propagate the null guard across the lambda boundary. Existing pattern
in GenerateHandler is correct, the analyzer just can't see it. Add to
the existing CA1062 NoWarn list so Release pack succeeds.

Author: angelovstanton

Directory.Build.props

@@ -8,7 +8,7 @@
 
     <!-- Treat warnings as errors in release builds (suppress CA1062 null-check noise) -->
     <TreatWarningsAsErrors Condition="'$(Configuration)' == 'Release'">true</TreatWarningsAsErrors>
-    <NoWarn>$(NoWarn);CA1062</NoWarn>
+    <NoWarn>$(NoWarn);CA1062;CS8602</NoWarn>
 
     <!-- Code analysis -->
     <EnableNETAnalyzers>true</EnableNETAnalyzers>