chore: cascade deletion on isbsvc pvc

[whynowy]

Starting from k8s v1.27, PVC auto deletion was introduced, became stable in v1.32. Hence we don't need to handle it any more.

Backward compatible with k8s < v1.27, verified in v1.26.

[codecov]

Codecov Report

Attention: Patch coverage is 48.00000% with 13 lines in your changes missing coverage. Please review.

Project coverage is 67.06%. Comparing base (677cc59) to head (02ae274).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/apis/numaflow/v1alpha1/deprecated.go	0.00%	7 Missing ⚠️
pkg/reconciler/isbsvc/installer/jetstream.go	40.00%	2 Missing and 1 partial ⚠️
pkg/reconciler/isbsvc/installer/native_redis.go	40.00%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2305      +/-   ##
==========================================
- Coverage   67.07%   67.06%   -0.01%     
==========================================
  Files         349      349              
  Lines       44969    44992      +23     
==========================================
+ Hits        30162    30176      +14     
- Misses      13735    13750      +15     
+ Partials     1072     1066       -6     

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