[flutter_adaptive_scaffold] Add additional slot animation parameters

[jamiewest]

Slots can currently be animated in and out of view, but there is not an ability to change the duration or curves of these animations. This PR adds additional parameters that are passed to the underlying AnimatedSwitcher when switching slots in and out of view.

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[flutter-dashboard]

It looks like this pull request may not have tests. Please make sure to add tests before merging. If you need an exemption to this rule, contact "@test-exemption-reviewer" in the #hackers channel in Chat (don't just cc them here, they won't see it! Use Discord!).

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[gspencergoog]

@jamiewest Thanks for the PR! Seems like a good addition.

As the bot mentioned, however, it will need to have tests before I can review it, according to our Tree Hygiene guide.

[stuartmorgan-g]

Marking as a draft since per the comment above this is not yet ready for review. Please mark it as ready once the tests have been added. Thanks!

[martijn00]

Does this implement flutter/flutter#114272 ?

[martijn00]

@gspencergoog after my other 2 PRs are merged i'll pick this up and add some tests. Should be good to take in for the next release as well.

[stuartmorgan-g]

Since this is marked as a draft and hasn't been updated in several months I'm going to close it to clean out our review queue. Please don't hesitate to submit a new PR if you decide to revisit this. Thanks!

[martijn00]

@stuartmorgan this was fixed and closed through #7411