fix: ExitHandler support on workflowtempalteRef

[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". WorklowTemplate OnExit didn't work on WorkflowTemplateRef  #3259
• I've signed the CLA.
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• My organization is added to USERS.md.