[Neko] Neko uses :hearts: instead of :heart: when pet

Can reproduce Permissible. Refer to https://github.com/flutter/flutter/issues/100964#issuecomment-1443492371 and https://web.canary.fluxer.app/channels/1519773906704011264/1541839434838716417/1546646557082779648 for additional information.