First aggregate loses datetime precision

[ahey]

Describe the bug
When a first aggregate returns an attribute with type :utc_datetime_usec, precision is lost.

To Reproduce
A failing test has been created to easily demonstrate the issue.

1) test first aggregate maintains datetime precision (AshPostgres.AggregateTest)
     test/aggregate_test.exs:471
     Assertion with == failed
     code:  assert post.created_at == fetched_post.latest_comment_created_at
     left:  ~U[2023-11-13 03:46:05.332378Z]
     right: ~U[2023-11-13 03:46:05Z]
     stacktrace:
       test/aggregate_test.exs:494: (test)

The bug seems to have been introduced in ash by these changes.

Here is the most recent ash commit where the issue was not present

[zachdaniel]

Hmm...yeah this looks like an issue that needs resolving. We need to get aggregate constraints as well as types here.

[zachdaniel]

This is fixed in 2.17

[ahey]

Thanks Zach!