fix: hide navigation button when toolbar variant of AppLayout has hideNavigation

[dpitcock]

Description

Overview

• this hides the navigation toggle button when toolbar variant of AppLayout has hideNavigation prop of true.
• it also insures there is never a situation where a toolbar of AppLayout will exist with navigationOpen is true when navigationHide is true which is the case in some consoles. This insures the rendering is as expected in those consoles
• Also there is a new page added to human test the props, but not integration tests that use it for it is covered by unit tests

Other

• renaming mergeProps => mergeMultiAppLayoutProps and SharedProps => SharedMultiAppLayoutProps to be more specific and exporting them so they can be tested individually
• testing the mergeMultiAppLayoutProps in isolation
• testing the specific case of AppLayout where the navigationHide prop is true with the assertion that no navigation-panel nor navigation toggle is visible.

Related links, issue #, if available: n/a

How has this been tested?

Review checklist

The following items are to be evaluated by the author(s) and the reviewer(s).

Correctness

• Changes include appropriate documentation updates.
• Changes are backward-compatible if not indicated, see CONTRIBUTING.md.
• Changes do not include unsupported browser features, see CONTRIBUTING.md.
• Changes were manually tested for accessibility, see accessibility guidelines.

Security

• If the code handles URLs: all URLs are validated through the checkSafeUrl function.

Testing

• Changes are covered with new/existing unit tests?
• Changes are covered with new/existing integration tests?

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