Exclude artifacts & .packages folders from CodeQL scans (#56197)

Author: wtgodbe

.azure/pipelines/ci.yml

@@ -114,6 +114,11 @@ variables:
 - ${{ if in(variables['Build.Reason'], 'PullRequest') }}:
   - name: _SignType
     value: test
+# Exclude artifacts & .packages folders from CodeQL scans
+- name: LGTM_INDEX_FILTERS
+  value: |
+    exclude:.packages
+    exclude:artifacts
 - template: /eng/common/templates-official/variables/pool-providers.yml@self
 
 resources: