fix(ty): Fix ty-reported static type issues

[janickm]

This pull request focuses on improving type safety and code clarity by adding explicit type casting, especially for generic metadata and data structures. It also includes minor type annotation cleanups and imports to ensure correctness and maintainability.

Type safety and explicit casting improvements:

• Added explicit cast calls to Dict[str, JsonLike] for all generic metadata arguments in components_test.py to clarify types and prevent type-checking errors. [1] [2] [3] [4] [5] [6] [7] [8] [9]
• Updated the assertion in test_generic_data_and_metadata to cast the loaded quality value to float before comparison, ensuring type correctness.

Type annotation and import cleanups:

• Added cast to the test imports to support new explicit casts.
• Updated usages of timestamps_us in _get_frame_group to use cast(np.ndarray, ...) for better type clarity. [1] [2]
• Removed unnecessary cast to zarr.Group in get_frame_ray_bundle_return_data_names, simplifying the code.

Minor code cleanup:

• Removed unnecessary # type: ignore comment in types.py for a polynomial coefficient cast, as the type is now clear.