feat: override block component validator

[LucasXu0]

Changed the validator to be customizable and support overriding it.

This is helpful if you want to override the existing validator.

[codecov]

Codecov Report

Attention: Patch coverage is 75.00000% with 9 lines in your changes missing coverage. Please review.

Project coverage is 72.06%. Comparing base (0a0d441) to head (946fb9b).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...t/table_block_component/table_block_component.dart	65.38%	9 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #924   +/-   ##
=======================================
  Coverage   72.06%   72.06%           
=======================================
  Files         318      318           
  Lines       15000    15001    +1     
=======================================
+ Hits        10810    10811    +1     
  Misses       4190     4190           

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