feat: support setting clientAuthenticationMethod for OIDC

[dervoeti]

Description

Part of stackabletech/issues#838

The clientAuthenticationMethod field from the OIDC ClientAuthenticationOptions is currently deserialized but never used. This PR passes it through to the generated superset_config.py as token_endpoint_auth_method.

Basically the same as stackabletech/superset-operator#716

Requires an operator-rs release with stackabletech/operator-rs#1178.

Definition of Done Checklist

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Author

• Changes are OpenShift compatible
• CRD changes approved
• CRD documentation for all fields, following the style guide.
• Helm chart can be installed and deployed operator works
• Integration tests passed (for non trivial changes)
• Changes need to be "offline" compatible
• Links to generated (nightly) docs added
• Release note snippet added

Reviewer

• Code contains useful comments
• Code contains useful logging statements
• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

• Feature Tracker has been updated
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• Links to generated (nightly) docs added
• Release note snippet added
• Add type/deprecation label & add to the deprecation schedule
• Add type/experimental label & add to the experimental features tracker