fix: redis cluster update as scale out

[drivebyer]

Description

Fix redis cluster status not updated when scale out cluster size.

more: it's ok about to remove the statefulset assert step && ping pod step. We can test these only by redis cluster status

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• [x] 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

Attention: Patch coverage is 50.00000% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 38.70%. Comparing base (d121d86) to head (068d5a3). Report is 24 commits behind head on master.

Files	Patch %	Lines
controllers/rediscluster_controller.go	50.00%	3 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #872 +/- ## ========================================== + Coverage 35.20% 38.70% +3.50% ========================================== Files 19 19 Lines 3213 2656 -557 ========================================== - Hits 1131 1028 -103 + Misses 2015 1559 -456 - Partials 67 69 +2 ```

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