Fix Browse button layout

**Problem**

Browse button in Custom Object upload dialog displays weirdly
in portrait mode on iOS. It unexpectedly covers almost the entire
URL area in portrait mode.

**Solution**

The issue seems to disappear by removing the "width: 100%" from
the parent element style. The root issue might be in iOS,
but we choose this workaround for now.

src/react-components/room/ObjectUrlModal.scss

@@ -22,7 +22,6 @@
 
 :local(.container) {
   height: 100%;
-  width: 100%;
   margin: 0 !important;
 }