[RFC]: Update Bartlett test

[Planeshifter]

This RFC proposes refactoring the Bartlett test to align with improvements made to the chi-square test in commit 2a2186604e317e461b18afc23e41e9fa5e394c10.

Proposed Changes

Return class instance Instead of a plain object

• Replace the current plain object results with a proper Results class
• Implement accessors for all properties (alpha, statistic, pValue, df, etc.)
• Add proper TypeScript types for the Results class

API Changes

• Rename print method to toString for consistency
• Add toJSON method for serialization
• Keep the flexible argument handling

Performance Improvements

• Use stdlib's BLAS-like functions for summations and array operations
• Use typed arrays for numeric computations
• Optimize group data handling

Time estimate without AI: 2h.
Time estimate with AI: 1h.

[Planeshifter]

PR-URL: stdlib-js/stdlib#6056

Loom recording: https://www.loom.com/share/0240d77eb7df4973886ed7ff9af1629b?sid=f9a12908-d13c-41c1-b17d-8a613c5b58ae

Time to initial completion: 63min