Disable per-build validation (#3236)

Reduces build time. SDL is now right nightly + on each build candidate. No need to keep running on a per-build basis.

azure-pipelines.yml

@@ -75,15 +75,13 @@ stages:
 - ${{ if and(ne(variables['System.TeamProject'], 'public'), notin(variables['Build.Reason'], 'PullRequest')) }}:
   - template: eng\common\templates\post-build\post-build.yml
     parameters:
-      # Symbol validation isn't being very reliable lately. This should be enabled back
-      # once this issue is resolved: https://github.com/dotnet/arcade/issues/2871
       enableSymbolValidation: false
-      # Sourcelink validation isn't passing for Arcade due to some regressions. This should be
+      enableSigningValidation: false
-      # enabled back once this issue is resolved: https://github.com/dotnet/arcade/issues/2912
+      enableNugetValidation: false
       enableSourceLinkValidation: false
       # This is to enable SDL runs part of Post-Build Validation Stage
       SDLValidationParameters:
-        enable: true
+        enable: false
         params: ' -SourceToolsList @("policheck","credscan")
         -TsaInstanceURL $(_TsaInstanceURL)
         -TsaProjectName $(_TsaProjectName)