Fix type errors in operator link calls

[amoghrajesh]

Adds type: ignore comments to resolve mypy errors when calling BaseOperatorLink.get_link() with core operator types instead of the expected SDK BaseOperator type.

The BaseOperatorLink.get_link() method in the task SDK expects a BaseOperator parameter, but in the the references where we call it, we're passing:

• SerializedBaseOperator
• MappedOperator

For now, added type: ignore[arg-type] comments with TODO references to GH-52141, which tracks the broader issue of SDK/core type separation.

related #54295

Fixes CI errors:

airflow-core/src/airflow/serialization/serialized_objects.py:1300: error: Argument 1 to "get_link" of "BaseOperatorLink" has incompatible type "SerializedBaseOperator"; expected "BaseOperator" 
[arg-type]
            return link.get_link(self.unmap(None), ti_key=ti.key)
                                 ^~~~~~~~~~~~~~~~
airflow-core/src/airflow/models/mappedoperator.py:168: error: Argument 1 to "get_link" of "BaseOperatorLink" has incompatible type "MappedOperator"; expected "BaseOperator"  [arg-type]
            return link.get_link(self, ti_key=ti.key)
                                 ^~~~
Found 2 errors in 2 files (checked 982 source files)

Example: https://github.com/apache/airflow/actions/runs/16862119240/job/47764118285

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