Accessibility: Media: Hide the invisible "file upload button" on media views from assistive technologies.

The button is visually hidden, but was announced by screen readers in workflows unrelated to file uploading, leading to confusion.

Props afercia, audrasjb, azaozz.
Fixes #47611.

git-svn-id: https://develop.svn.wordpress.org/trunk@47375 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/css/media-views.css

@@ -1526,6 +1526,11 @@
 	display: inline-block !important;
 }
 
+div.moxie-shim.moxie-shim-html5,
+div.moxie-shim.moxie-shim-html5 input[type="file"] {
+	display: none;
+}
+
 /**
  * Selection
  */