FIX: "Listen" button listening for wrong type (ISX-1832).

[graham-huws]

Description

The "Listen" button would sometimes be listening to the wrong type of input. This was due to part of the code assuming that the selected item was an Action, when it would be a Binding. ISX-1832

Changes made

In GetSelectedAction, we now return the relevant "parent" action if the user had a Binding selected.

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

[Pauliusd01]

LGTM, checked listen button functionality with different types of bindings in ProjectWideActions/CustomInputActions