CI | Update Ceph S3 Tests Workflow

[shirady]

Explain the changes

1. Remove the comments about an open issue that was closed (Default Backing Store is in phase ready, but test pool cannot be used. noobaa-operator#1007).
2. Run a script to wait until we have the backingstore pod (in k8s we cannot wait for a resource that doesn't exist (more information here, based on the change we did in CI | Update Admission Tests Workflow noobaa-operator#1063).
3. Update operator repo to the latest commit.
4. Minor changes (adding a new line between 2 steps, removing redundant quotation marks).

Issues: Fixed #xxx / Gap #xxx

1. none.

Testing Instructions:

1. none, will be tested in the workflow.

• Doc added/updated
• Tests added

[liranmauda]

LGTM