2691 - Change Toolbar API's Teardown to respect noSearchfieldReinvoke setting

[EdwardCoyle]

Explain the details for making this change. What existing problem does the pull request solve?
This PR fixes a bug affecting Landmark where Toolbar components that use a noSearchfieldReinvoke setting (to pass responsibility of managing the Searchfield's lifecycle in a toolbar) was not being respected by the teardown method added in #2574. This PR fixes the teardown and allows the Searchfield to stay in-tact when this setting is passed.

Related github/jira issue (required):

• Related to Toolbar: Destroy test case not working and causes memory leak #2496
• Fixes Toolbar SearchField: Doesn't appear on page when noSearchfieldReinvoke used #2691

Steps necessary to review your pull request (required):

• Pull this branch, run app
• Open http://localhost:4000/components/toolbar/test-searchfield-no-reinvoke-update
• Test the functionality of the Searchfield to ensure that it's working.
• Click the button labelled "Update Toolbar"
• Re-test the functionality of the Searchfield to ensure it's still working.

Included in this Pull Request:

• An e2e or functional test for the bug or feature.
• A note to the change log.

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@paging @Sovia @pwpatton @lipetzan

[EdwardCoyle]

Note due to the time crunch, I raised #2692 for adding e2e/func tests for this separately.