Jenkinsfile bug fix (#910)

### Description
Coming from initial PR
#893
to exclude helm tags for triggering the jenkins promotion workflow, a
small bug caused the build failure
https://build.ci.opensearch.org/job/opensearch-operator-release/19/console.

The helm version update PR was merged
#754
causing it to create a tag and run the jenkins promotion workflow.

### Issues Resolved
#830

### Check List
- [x] Commits are signed per the DCO using --signoff 
- [ ] Unittest added for the new/changed functionality and all unit
tests are successful
- [ ] Customer-visible features documented
- [ ] No linter warnings (`make lint`)

If CRDs are changed:
- [ ] CRD YAMLs updated (`make manifests`) and also copied into the helm
chart
- [ ] Changes to CRDs documented

Please refer to the [PR
guidelines](https://github.com/opensearch-project/opensearch-k8s-operator/blob/main/docs/developing.md#submitting-a-pr)
before submitting this pull request.

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and
signing off your commits, please check
[here](https://github.com/opensearch-project/OpenSearch/blob/main/CONTRIBUTING.md#developer-certificate-of-origin).

Signed-off-by: Prudhvi Godithi <[email protected]>

jenkins/release.jenkinsfile

@@ -67,7 +67,7 @@ pipeline {
                     }
 
 
-                    if (ref_final == null || ref_final == '' || ref_final.startsWith('opensearch-operator') || ref_final.startsWith('opensearch-cluster')) { {
+                    if (ref_final == null || ref_final == '' || ref_final.startsWith('opensearch-operator') || ref_final.startsWith('opensearch-cluster')) {
                         currentBuild.result = 'ABORTED'
                         error("Missing git tag reference.")
                     }