UI: Don't stretch server field in Qt 5.14

UI/forms/OBSBasicSettings.ui

@@ -958,6 +958,12 @@
              </item>
              <item row="0" column="1">
               <widget class="QStackedWidget" name="serverStackedWidget">
+               <property name="sizePolicy">
+                <sizepolicy hsizetype="Preferred" vsizetype="Maximum">
+                 <horstretch>0</horstretch>
+                 <verstretch>0</verstretch>
+                </sizepolicy>
+               </property>
                <property name="currentIndex">
                 <number>1</number>
                </property>