UI: Clean up Custom Browser Docks form markup

Minor alphabetical rearrange by Qt Creator

UI/forms/OBSExtraBrowsers.ui

@@ -29,10 +29,10 @@
      <property name="selectionMode">
       <enum>QAbstractItemView::NoSelection</enum>
      </property>
-     <attribute name="horizontalHeaderDefaultSectionSize">
+     <attribute name="horizontalHeaderMinimumSectionSize">
       <number>23</number>
      </attribute>
-     <attribute name="horizontalHeaderMinimumSectionSize">
+     <attribute name="horizontalHeaderDefaultSectionSize">
       <number>23</number>
      </attribute>
      <attribute name="verticalHeaderVisible">