[FEM] fix Centrif dialog size

- reduce to a sensible size and get git on unneeded spacer

src/Mod/Fem/Gui/Resources/ui/ConstraintCentrif.ui

@@ -6,8 +6,8 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>350</width>
-    <height>500</height>
+    <width>259</width>
+    <height>73</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -104,19 +104,6 @@
      </layout>
     </widget>
    </item>
-   <item>
-    <spacer name="verticalSpacer_2">
-     <property name="orientation">
-      <enum>Qt::Vertical</enum>
-     </property>
-     <property name="sizeHint" stdset="0">
-      <size>
-       <width>20</width>
-       <height>40</height>
-      </size>
-     </property>
-    </spacer>
-   </item>
   </layout>
  </widget>
  <customwidgets>