fix: Panic on invalid WorkflowTemplateRef

[sarabala1979]

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this is a chore.
• The title of the PR is (a) conventional, (b) states what changed, and (c) suffixes the related issues number. E.g. "fix(controller): Updates such and such. Fixes #1234". deletePDBResource panics if workflowRef not found #3121
• I've signed the CLA.
• I have written unit and/or e2e tests for my change. PRs without these are unlikely to be merged.
• My builds are green. Try syncing with master if they are not.
• My organization is added to USERS.md.

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!

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0 Vulnerabilities (and 0 Security Hotspots to review)
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100.0% Coverage
0.0% Duplication