Fix validation of Literal from JSON keys when used as dict key

[sydney-runkle]

Change Summary

Fix bug introduced in pydantic v2.5 such that when a Literal type is used as the key for a dictionary, a validation error was raised when validating JSON (when the correct value was provided).

Related issue number

Fix #pydantic/pydantic#8133

Checklist

• Unit tests for the changes exist
• Documentation reflects the changes where applicable
• Pydantic tests pass with this pydantic-core (except for expected changes)
• My PR is ready to review, please add a comment including the phrase "please review" to assign reviewers

Selected Reviewer: @davidhewitt

[codecov]

Codecov Report

Merging #1075 (8ba84cb) into main (73b1184) will increase coverage by 0.00%.
Report is 1 commits behind head on main.
The diff coverage is 100.00%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1075   +/-   ##
=======================================
  Coverage   89.63%   89.63%           
=======================================
  Files         106      106           
  Lines       16391    16397    +6     
  Branches       35       35           
=======================================
+ Hits        14692    14698    +6     
  Misses       1692     1692           
  Partials        7        7           

Files	Coverage Δ
src/validators/literal.rs	93.05% <100.00%> (+0.14%)	⬆️

... and 1 file with indirect coverage changes

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[codspeed-hq]

CodSpeed Performance Report

Merging #1075 will improve performances by 16.04%

_{Comparing fix-literal-from-json-keys (8ba84cb) with main (73b1184)}

Summary

⚡ 1 improvements
✅ 139 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	fix-literal-from-json-keys	Change
⚡	test_small_class_core_model	57.4 µs	49.4 µs	+16.04%

[sydney-runkle]

Please review