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.
• Functionality/bugs have been confirmed to be unchanged or fixed.
• I have performed a self-review of my own code.
• Documentation has been updated or added where necessary.

Additional Context

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

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

Additional details and impacted files

@@            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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