FIX: ISXB-621 disable all action maps except default map when input system is started

[smnwttbr]

Description

When the InputSystem MonoBehaviour is enabled, all actions maps default to enabled. Only the default action map should be enabled. ISXB-621

Changes made

TODO

Checklist

Before review:

• [x] 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.

[ekcoh]

I need to dig deeper into associated repro to understand fully the problem and suggested fix.... I will return to this PR.

[Pauliusd01]

@stefanunity hey, could you take a look at this if you have the free time? If not I can still take a look but it will take a while till I can come around to this