[Site design revamp] Remove unused string resource hpp_subtitle#16419

mkevins merged 1 commit intofeature/site-design-revamp--remove-thumbnail-mode-selectorwordpress-mobile/WordPress-Android:feature/site-design-revamp--remove-thumbnail-mode-selectorfrom

pr/16414-remove-unused-string-reswordpress-mobile/WordPress-Android:pr/16414-remove-unused-string-resCopy head branch name to clipboard