fix: runtime panic when delete rediscluster which disable persistent

[drivebyer]

Description

Fixes #921

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist

• [ ] Tests have been added/modified and all tests pass.
• [x] Functionality/bugs have been confirmed to be unchanged or fixed.
• [x] I have performed a self-review of my own code.
• [ ] Documentation has been updated or added where necessary.

Additional Context

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 39.75%. Comparing base (d121d86) to head (833545b). Report is 44 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #922 +/- ## ========================================== + Coverage 35.20% 39.75% +4.55% ========================================== Files 19 19 Lines 3213 2674 -539 ========================================== - Hits 1131 1063 -68 + Misses 2015 1540 -475 - Partials 67 71 +4 ```

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