Added support for Enum types in Pydantic models

[AdilFayyaz]

Tracking issue

Duplicated from: flyteorg/flyte-sdk/pull/622

Why are the changes needed?

Ensure flytekit versions alongside flytesdk

What changes were proposed in this pull request?

In generate_attribute_list_from_dataclass_json_mixin(), when a $ref resolves to an enum definition (has enum key, no properties), map the field to str instead of trying to construct a dataclass from it. Previously this crashed with KeyError: 'properties' because the code assumed every $ref pointed to a model.

How was this patch tested?

Test (test_enum_in_pydantic.py): Defines a Job(BaseModel) with a Status(str, Enum) field, roundtrips it through to_literal_type -> to_literal -> to_python_value -> guess_python_type, and verifies the guessed dataclass accepts enum values as strings.

Setup process

Screenshots

Check all the applicable boxes

• I updated the documentation accordingly.
• All new and existing tests passed.
• All commits are signed-off.

Related PRs

Docs link

[codecov]

Codecov Report

❌ Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 47.80%. Comparing base (ba7dc6f) to head (83826a5).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
flytekit/core/type_engine.py	0.00%	3 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (ba7dc6f) and HEAD (83826a5). Click for more details.

HEAD has 49 uploads less than BASE

Flag	BASE (ba7dc6f)	HEAD (83826a5)
	50	1

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #3391       +/-   ##
===========================================
- Coverage   82.87%   47.80%   -35.07%     
===========================================
  Files         356      216      -140     
  Lines       29579    22782     -6797     
  Branches     2997     2998        +1     
===========================================
- Hits        24513    10892    -13621     
- Misses       4218    11295     +7077     
+ Partials      848      595      -253     

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