feat(DataTable): add full table ai support

[matthewgallo]

Closes #19485

This PR includes a new prop on the TableContainer (aiEnabled) that adds the ai gradient across the table body and a gradient border effect to the table container.

New full gradient AI story

Changelog

New

• New story showing full table gradient
• aiEnabled prop added to TableContainer
• Test added to TableContainer-test.js
• API snapshot updated
• utilities.ai-table-gradient sass mixin updated to support a vertical gradient direction, used for the full table gradient

Testing / Reviewing

Visually verify from new story and manually run TableContainer tests

PR Checklist

As the author of this PR, before marking ready for review, confirm you:

• [X] Reviewed every line of the diff
• [X] Updated documentation and storybook examples
• [X] Wrote passing tests that cover this change
• [ ] Addressed any impact on accessibility (a11y)
• [X] Tested for cross-browser consistency
• [X] Validated that this code is ready for review and status checks should pass

More details can be found in the pull request guide

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 84.69%. Comparing base (624890b) to head (919d101). Report is 38 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #19615   +/-   ##
=======================================
  Coverage   84.68%   84.69%           
=======================================
  Files         373      373           
  Lines       14709    14710    +1     
  Branches     4845     4847    +2     
=======================================
+ Hits        12457    12458    +1     
+ Misses       2102     2101    -1     
- Partials      150      151    +1     

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