[WIP] Schema version priority for union dataclass comparison

[mao3267]

Tracking issue

flyteorg/flyte#5489

Why are the changes needed?

Since we plan to primarily support newer versions of JSON schemas in the future, we would like to update the JSON schema version priority in the literal metadata field.

What changes were proposed in this pull request?

1. We are modifying the priority for generating JSON schemas. Initially, the schema from Marshmallow, which follows draft-7, was prioritized. Moving forward, we will prioritize the schema from Mashumaro, which adheres to the newer draft 2020-12 specification.
2. Update related unit tests to make sure everything works as expected.
3. Fix missing logic for dict while generating attribute list in generate_attribute_list_from_dataclass_json_mixin function.

How was this patch tested?

1. Pass existing tests and modified tests

Setup process

git clone https://github.com/flytorg/flytekit.git
gh pr checkout 2952
pip install -e .

Screenshots

Check all the applicable boxes

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

Related PRs

#2932
#2859

Docs link

None