add declare for emoji-mart

packages/editor/src/@types/declaration.d.ts

@@ -1,2 +1,5 @@
 // prevent TS2307: Cannot find module './xxx.module.scss' or its corresponding type declarations.
 declare module '*.scss';
+
+// prevent TS7016: Could not find a declaration file for module 'emoji-mart'.
+declare module 'emoji-mart';