fix: trufflehog --only-verified (#286)

Recently multiple false positives reported for trufflehog v3:
https://splunk.slack.com/archives/CRTNPEZ4M/p1717405810934429

Let's add --only-verified flag to callout to avoid multiple fp for now.
Final solution need to be established/reviewed with prodsec.
More info on secrets verification in trufflehog:
https://trufflesecurity.com/blog/how-trufflehog-verifies-secrets

Tests:
https://github.com/splunk/splunk-add-on-for-microsoft-office-365/actions/runs/9399856169

.github/workflows/reusable-build-test-release.yml

@@ -267,7 +267,7 @@ jobs:
       - name: Secret Scanning Trufflehog
         uses: trufflesecurity/[email protected]
         with:
-          extra_args: -x .github/workflows/exclude-patterns.txt --json
+          extra_args: -x .github/workflows/exclude-patterns.txt --json --only-verified
           version: 3.77.0
 
   semgrep: