Don't unconditionally call `preventDefault` and `stopPropagation` on all keyup events (#4777)

* UploadArea should only preventDefault for Escape

This will make accessibility for some things less effortful, since we won't have to define a prior event handler to do whatever should be happening by default.

* Remove workaround for fixed bug in SettingToggle

SettingToggle was toggling itself in response to keydown of space, and then the keyup was doing it again

app/javascript/mastodon/features/notifications/components/setting_toggle.js

@@ -18,12 +18,6 @@ export default class SettingToggle extends React.PureComponent {
     this.props.onChange(this.props.settingKey, target.checked);
   }
 
-  onKeyDown = e => {
-    if (e.key === ' ') {
-      this.props.onChange(this.props.settingKey, !e.target.checked);
-    }
-  }
-
   render () {
     const { prefix, settings, settingKey, label, meta } = this.props;
     const id = ['setting-toggle', prefix, ...settingKey].filter(Boolean).join('-');

app/javascript/mastodon/features/ui/components/upload_area.js

@@ -12,13 +12,12 @@ export default class UploadArea extends React.PureComponent {
   };
 
   handleKeyUp = (e) => {
-    e.preventDefault();
-    e.stopPropagation();
-
     const keyCode = e.keyCode;
     if (this.props.active) {
       switch(keyCode) {
       case 27:
+        e.preventDefault();
+        e.stopPropagation();
         this.props.onClose();
         break;
       }