Fix keyboard navigation when using menu dropdown with multiple option

[jroofsf]

Fixes #

Fixes keyboard navigation in menu dropdown component when using the multiple option.

Additional description

Fixes this issue: Use the keyboard to select an option in the menu dropdown component. Use the keyboard's up or down arrow keys to advance to the next or previous item. The focus jumps to the first item in the list when pressing the down arrow key or to the last item when pressing the up arrow key.

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[welcome]

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[salesforce-cla]

Thanks for the contribution! Before we can merge this, we need @jroofsf to sign the Salesforce Inc. Contributor License Agreement.

[interactivellama]

Works great!

[welcome]

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