fix: compatibility with pydantic v2

[dagondagon666]

What this PR does / why we need it:

• Follows Optional fields guidance for pydantic v2 ref
• Overwrites protected_namespace in pydantic v2 to get rid of warning logs about namespace conflicts in pydantic ref. An example is shown as follows

E   UserWarning: Field "model_name" has conflict with protected namespace "model_".
E
E   You may be able to resolve this warning by setting `model_config['protected_namespaces'] = ()`.

Type of changes
Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Special notes for your reviewer:

1. Please confirm that if this PR changes any image versions, then that's the sole change this PR makes.
   No image version increase

Checklist:

• Have you added unit/e2e tests that prove your fix is effective or that this feature works?
• Has code been commented, particularly in hard-to-understand areas?
• Have you made corresponding changes to the documentation?

Release note:

NONE

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[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: dagondagon666
Once this PR has been reviewed and has the lgtm label, please assign yuzisun for approval by writing /assign @yuzisun in a comment. For more information see:The Kubernetes Code Review Process.

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[dagondagon666]

/assign @yuzisun

[terrytangyuan]

Could you add a test for this?

[terrytangyuan]

Should we surround the imports with try-catch in for backwards compatibility purposes?

[timothyjlaurent]

If we do -- we should likely also likely add if/else for the the class definitions to switch from the nested Config class to model_config

[yuzisun]

Why do we need the model_config ?

[timothyjlaurent]

This is the new syntax for pydantic 2 that's analogous to the nested Config class in pydantic 1.

My guess is that Pydantic2 uses "model_" a protected namespace which we need for model_version

[timothyjlaurent]

This is to suppress this warning:

E   UserWarning: Field "model_name" has conflict with protected namespace "model_".
E
E   You may be able to resolve this warning by setting `model_config['protected_namespaces'] = ()`.

So it really ought to be an empty tuple.

[timothyjlaurent]

This is pydantic 1 syntax.

We should move the schema_extra into the json_schema_extra field in the model_config above.

https://docs.pydantic.dev/latest/migration/#changes-to-config

[timothyjlaurent]

We need to replace Config with model_config if we want it to work in pydantic 2

[sivanantha321]

closing in favor of #3374