[Cloud Security] unskip old data e2e tests for csp plugin (#172064)

## Summary

Closes:
- #171737

tests should be fixed with
https://github.com/elastic/kibana/pull/171736/files,

flaky test runner
https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/4098

Co-authored-by: Kibana Machine <[email protected]>

x-pack/test/cloud_security_posture_functional/pages/findings_old_data.ts

@@ -55,7 +55,7 @@ export default function ({ getPageObjects }: FtrProviderContext) {
     },
   ];
 
-  describe.skip('Old Data', function () {
+  describe('Old Data', function () {
     this.tags(['cloud_security_posture_findings']);
     let findings: typeof pageObjects.findings;