Reuse secret instead of creating every time

[damccorm]

Creating a secret test resource every time leads to occasional synchronization failures (see #35832 (comment)). This fixes the problem.

Fixes #35832

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[shunping]

LGTM.

[Amar3tto]

@damccorm should we cherrypick?

[damccorm]

If its causing failures on the release branch, then sure. But this was a fix for an occasional flake, so I think it is fine to leave if you're not seeing issues