fix(openapi): support prefixItems for tuple schema

[Jannchie]

• resolved Bug: OpenAPI Schema Generation Incorrect for Tuple Type Hint #4130

The previous implementation incorrectly treated Python tuples as arrays with items of a single, uniform type.

This change utilizes prefixItems (OpenAPI 3.1+) to correctly specify the type for each element at its specific position when the field is a tuple. This results in a more accurate and modern OpenAPI schema that precisely reflects the Python tuple structure.

Additionally:

• Adjusted assertions in test_schema_tuple_with_union as the original expectations seemed incorrect with the proper schema generation.
• Added a new test case test_schema_tuple.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.37%. Comparing base (6129482) to head (194a6ab).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4132   +/-   ##
=======================================
  Coverage   98.37%   98.37%           
=======================================
  Files         348      348           
  Lines       15857    15859    +2     
  Branches     1751     1752    +1     
=======================================
+ Hits        15599    15601    +2     
  Misses        123      123           
  Partials      135      135           

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[github-actions]

Documentation preview will be available shortly at https://litestar-org.github.io/litestar-docs-preview/4132