CHANGE: Update Input for UI provider to use project-wide input actions

[jfreire-unity]

Description

ISX-1528

Changes made

• Change InputSystemProvider for Input For UI module to work with the Project Wide Actions instead of DefaultInputActions. This makes UI TK use project-wide action bindings that can be modified by users.

• Added some warnings when the asset is saved with changes to the "UI" action maps. By doing this only in save, it makes sure that other parts of the code are decoupled from Project Wide Actions.

❓

• Should there be a way to reset specific action maps? Besides having just "Reset", also have "Reset UI map" and "Reset Player map" as well?
• Some might prefer to have an Editor UI visual warning (e.g. like a warning icon) when the UI action map is modified. But that would take more time than expected, as it involves UI TK UI changes. Please let me know if there should be any extra effort to change the UI.

Notes

ℹ️ The project to be used for QA is specified in the JIRA ticket.

I'll add doc changes in another PR after talking with Ben Pitt.

Checklist

Before review:

• Changelog entry added.
  • Explains the change in Changed, Fixed, Added sections.
  • For API change contains an example snippet and/or migration example.
  • FogBugz ticket attached, example ([case %number%](https://issuetracker.unity3d.com/issues/...)).
  • FogBugz is marked as "Resolved" with next release version correctly set.
• Tests added/changed, if applicable.
  • Functional tests Area_CanDoX, Area_CanDoX_EvenIfYIsTheCase, Area_WhenIDoX_AndYHappens_ThisIsTheResult.
  • Performance tests.
  • Integration tests.
• Docs for new/changed API's.
  • Xmldoc cross references are set correctly.
  • Added explanation how the API works.
  • Usage code examples added.
  • The manual is updated, if needed.

During merge:

• Commit message for squash-merge is prefixed with one of the list:
  • NEW: ___.
  • FIX: ___.
  • DOCS: ___.
  • CHANGE: ___.
  • RELEASE: 1.1.0-preview.3.

[ritamerkl]

LGTM

[ekcoh]

Looks good in general. I think we can skip the caching or was it taking a long time that drived the decision to cache in s_DefaultUIMap?

I also believe it would be good to add a test to cover CheckFirDefaultUIActionMapChanges.

[ekcoh]

Another one, CHANGELOG.md entry seems to be missing.

[jamesmcgill]

I think for the first pass, it is enough that InputForUI just uses InputSystem.actions.

UI improvements like blocking editing the UI action names, warnings, or resetUI map, would take more time.

[jfreire-unity]

@Pauliusd01 regarding testing, you can try to play around with removing the UI action map, UI actions, or changing the bindings like we discussed in the daily sync.

You should still see the events in the right column the Visualizer test project scene. And should get appropriate warning and error messages. There are already some warning messages once the asset is saved and you rename the UI action map and its actions.

[jfreire-unity]

@Pauliusd01 I put the wrong image before, I updated it now

[ekcoh]

In general looks good to me, happy to see some test coverage added. Two minor comments that I believe can improve the PR slightly.

[ekcoh]

I think this is expected given the solution we have previously discussed but its unfortunate since the action is basically required (driven by the implementation). In the long run I believe we should consider design changes that would allow the integration to own the action while the editor would allow reconfiguring it.

[ekcoh]

For the CHANGED message I believe it could be more clear to users if you added the delta to the description, e.g. "UI toolkit now uses the "UI" action map of project-wide actions as their default input actions instead of..." basically highlighting the switch from hard-coded to customisable.