enhance: clear pods which shardingconfig is not found

[Eikykun]

What type of PR is this?

/kind feature

What this PR does / why we need it:

Delete sharding pods after ShardingConfig deleted

Special notes for your reviewer:

Does this PR introduce a user-facing change?

Additional documentation e.g., design docs, usage docs, etc.:

[codecov]

Codecov Report

Attention: 32 lines in your changes are missing coverage. Please review.

Comparison is base (24cb737) 43.14% compared to head (e200574) 42.37%.
Report is 1 commits behind head on main.

Files	Patch %	Lines
.../shardingconfigserver/shardingconfig_controller.go	0.00%	32 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #27      +/-   ##
==========================================
- Coverage   43.14%   42.37%   -0.78%     
==========================================
  Files          26       26              
  Lines        2788     2820      +32     
==========================================
- Hits         1203     1195       -8     
- Misses       1479     1517      +38     
- Partials      106      108       +2     

Flag	Coverage Δ
unittests	42.37% <0.00%> (-0.78%)	⬇️

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