[web] Fix closing MultimediaModal on ESC press bug

Summary:
Fix for [ENG-4327](https://linear.app/comm/issue/ENG-4327/allow-esc-to-close-imagemodal-on-web).

This diff solves the issue, where closing MultimediaModal with the ESC key was impossible.

Test Plan: In chat, click on the image and when MultimediaModal is shown, check if ESC key press closes it. Tested on unencrypted and encrypted images.

Reviewers: bartek, tomek, ashoat

Reviewed By: ashoat

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D8498

web/media/media.css

@@ -103,6 +103,9 @@ div.multimediaModalOverlay > .mediaContainer {
   width: 100%;
   height: 100%;
 }
+div.multimediaModalOverlay > .mediaContainer:focus {
+  outline: none;
+}
 div.mediaContainer > img,
 div.mediaContainer > video {
   width: auto;

web/media/multimedia-modal.react.js

@@ -126,10 +126,13 @@ class MultimediaModal extends React.PureComponent<Props, State> {
       <div
         className={css.multimediaModalOverlay}
         onClick={this.onBackgroundClick}
-        tabIndex={0}
-        onKeyDown={this.onKeyDown}
       >
-        <div ref={this.overlayRef} className={css.mediaContainer}>
+        <div
+          ref={this.overlayRef}
+          className={css.mediaContainer}
+          tabIndex={0}
+          onKeyDown={this.onKeyDown}
+        >
           {mediaModalItem}
         </div>
         <XCircleIcon