feat(challenge modal): close with escape key

src/components/challenge-modal/challenge-modal.tsx

@@ -1,4 +1,4 @@
-import { useRef, useState } from 'react';
+import { useRef, useState, useEffect } from 'react';
 import Draggable from 'react-draggable';
 import { useTranslation } from 'react-i18next';
 import { Challenge as ChallengeType } from '@plebbit/plebbit-react-hooks';
@@ -52,6 +52,16 @@ const Challenge = ({ challenge, closeModal }: ChallengeProps) => {
     }
   };
 
+  useEffect(() => {
+    const onEscapeKey = (e: KeyboardEvent) => {
+      if (e.key === 'Escape') {
+        closeModal();
+      }
+    };
+    document.addEventListener('keydown', onEscapeKey);
+    return () => document.removeEventListener('keydown', onEscapeKey);
+  }, [closeModal]);
+
   // react-draggable requires a ref to the modal node
   const nodeRef = useRef(null);
   const isMobile = useIsMobile();