Fix toggle Folder mode control bar button not having a key

[ianyong]

Description

Resolves the following warning in console:

Warning: Each child in a list should have a unique "key" prop

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Code quality improvements

How to test

Check that the warning no longer appears in the console.

[coveralls]

Pull Request Test Coverage Report for Build 4522483781

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 35.029%

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Totals
Change from base Build 4522480025:	0.0%
Covered Lines:	4726
Relevant Lines:	12570

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💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 4510952662

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 34.881%

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Totals
Change from base Build 4508399233:	0.0%
Covered Lines:	4691
Relevant Lines:	12533

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💛 - Coveralls