[STRATCONN-5488] Introduces batch_keys field (pilot)

[varadarajan-tw]

This PR

• updates fields type in ActionDefinition to specify specific shape for batch_keys
• adds some validations for batch_keys field so that we can catch configuration errors earlier.

Testing

Scenario: 2

• Added unit tests for new functionality
• Tested end-to-end using the local server
• [If destination is already live] Tested for backward compatibility of destination. Note: New required fields are a breaking change.
• [Segmenters] Tested in the staging environment
• [Segmenters] [If applicable for this change] Tested for regression with Hadron.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 14 lines in your changes missing coverage. Please review.

Project coverage is 78.85%. Comparing base (25c9d2a) to head (904b779).
Report is 17 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/cli/src/commands/validate.ts	0.00%	14 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2791      +/-   ##
==========================================
+ Coverage   78.36%   78.85%   +0.49%     
==========================================
  Files        1042     1095      +53     
  Lines       18937    21718    +2781     
  Branches     3646     4364     +718     
==========================================
+ Hits        14840    17126    +2286     
- Misses       2860     3349     +489     
- Partials     1237     1243       +6     

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