Media: On Media Settings screen, make the pairs of labels and inputs always stacked vertically, on both mobile and desktop screens.

Make `<br />` tags on the screen behave as line breaks again after [41836]. Add a missing fieldset + legend for better accessibility.

Props afercia, RavanH, obenland, garrett-eclipse.
Fixes #42724. See #34539.
Built from https://develop.svn.wordpress.org/trunk@42864


git-svn-id: http://core.svn.wordpress.org/trunk@42694 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/css/forms.css

@@ -438,7 +438,15 @@ fieldset label,
 	vertical-align: middle;
 }
 
-.options-media-php label[for*="_size_"],
+.options-media-php [for*="_size_"] {
+	min-width: 10em;
+	vertical-align: baseline;
+}
+
+.options-media-php .small-text[name*="_size_"] {
+	margin: 0 0 1em;
+}
+
 #misc-publishing-actions label {
 	vertical-align: baseline;
 }