Support wider variety of enum validation cases

[sydney-runkle]

Alternative to #1324, thanks @mikeleppane for some of the tests here! Basically, fall back to trying to SomeEnum(input_value), and if that's valid, then return that value. This enables the use of custom __new__ functions as well :).

Fix pydantic/pydantic#9559
Fix pydantic/pydantic#9572
Fix pydantic/pydantic#9248

These to be addressed separately, in another PR soon that deals with the Literal validator:

• Coercion of Literal with StrEnum and str is not consistent pydantic#9989
• Different behaviour when using Literal and Enum and StrEnum pydantic#9791
• validate_call trying to parse an enum.StrEnum as an int pydantic#9437

[codspeed-hq]

CodSpeed Performance Report

Merging #1456 will not alter performance

_{Comparing enum-fixes (c4fc1a5) with main (e0b4c94)}

Summary

✅ 155 untouched benchmarks

[sydney-runkle]

Interesting, getting a test failure in v3.13 bc of this difference:

https://github.com/python/cpython/blob/6abddd9f6afdddc09031989e0deb25e301ecf315/Lib/enum.py#L1132-L1134 vs https://github.com/python/cpython/blob/ec610069637d56101896803a70d418a89afe0b4b/Lib/enum.py#L1159-L1163.