Dequeue render blocking styles

The change in If9c8f0974e3a4b08e4a66d37f7f5adf67d73054e
will introduce styles that are incompatible with Minerva due
to the blanking of the content array. The styles content
array should also be blanked.

Bug: T42812
Change-Id: I3388c3c4f91cdbab11e89cdc95973b688d3f1ce7

includes/skins/SkinMinerva.php

@@ -1377,6 +1377,8 @@ class SkinMinerva extends SkinTemplate implements ICustomizableSkin {
 		$modules = parent::getDefaultModules();
 		// dequeue default content modules (toc, sortable, collapsible, etc.)
 		$modules['content'] = [];
+		// dequeue styles associated with `content` key.
+		$modules['styles']['content'] = [];
 		// dequeue default watch module (not needed, no watchstar in this skin)
 		$modules['watch'] = [];
 		// disable default skin search modules