MappedOperator setter methods

[nathadfield]

Closes #37013

Addresses this issue referenced that prevents cluster policies from modifying attributes on dynamically mapped tasks by adding lots of additional setter methods to the MappedOperator.

[uranusjr]

It might be easier to just make these normal instance attributes like task_id, task_group instead of living one level below.

[jscheffl]

I do not understand the proposal of @uranusjr in the comment but from my review this looks like a good fix for the reported problem. Does not fix my other problem as discussed in #32471 but still good to go.

[uranusjr]

Many set-able members on MappedOperator are extracted from partial_kwargs into their own attributes on the class instead. For example, dag is popped out in OperatorPartial and set separately as its own attribute.

I can clean these up in a separate PR instead though.