UI refresh for uploaded files

Fixes https://github.com/vector-im/element-web/issues/16557
Fixes https://github.com/vector-im/element-web/issues/9482 (technically)

There's two changes in this:
1. The actual file body in the timeline now has a placeholder thing.
2. We're intentionally dropping all the "Travis uploaded a file" sender profile states.

src/components/views/messages/MAudioBody.js

@@ -105,7 +105,7 @@ export default class MAudioBody extends React.Component {
         return (
             <span className="mx_MAudioBody">
                 <audio src={contentUrl} controls />
-                <MFileBody {...this.props} decryptedBlob={this.state.decryptedBlob} />
+                <MFileBody {...this.props} decryptedBlob={this.state.decryptedBlob} showGenericPlaceholder={false} />
             </span>
         );
     }