Fix SPP worker bug in 17.8

What does this MR do and why?

Merge approved MR fixing a bug into 17.8. The MR is Fix nil input in causing SetGroupSecretPushProt... (!178423 - merged) • Gal Katz • 17.9

Relevant issue - Group security settings API for secret push pro... (#524547 - closed) • Gal Katz • 18.0

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• This MR is backporting a bug fix, documentation update, or spec fix, previously merged in the default branch.
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• Ensure the e2e:test-on-omnibus-ee job has either succeeded or been approved by a Software Engineer in Test.

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