fix(OverflowMenu): cleanup timeout upon unmount (#2259)
fix(OverflowMenu): cleanup timeout upon unmount (#2259)

Fixes #2114.
carbon-design-system/carbon-components-react,carbon-design-system/carbon-components,joshblack/carbon-components-react,carbon-design-system/carbon-components-react,carbon-design-system/carbon-components,joshblack/carbon-components-react,carbon-design-system/carbon-components