Convert CopyableInput to a function component

[lindapaiste]

Progress on #2358

Changes:

• Convert CopyableInput to a function component.
• Initialize the clipboard instance with a useEffect and a useRef.
• Set the tooltip classnames based on React state rather than manually adding and removing classes (see Avoid direct modification of HTML #2174 ).

I have verified that this pull request:

• has no linting errors (npm run lint)
• has no test errors (npm run test)
• is from a uniquely-named feature branch and is up to date with the develop branch.
• is descriptively named and links to an issue number, i.e. Fixes #123

[PiyushChandra17]

LGTM!

[raclim]

Thanks for working on this!