Fix pad properties dialog control updating.

This fixes an issue (at least on GTK builds) where the hidden controls
that change when selecting a different pad type and or pad shape get
shown are not laid out correctly.

pcbnew/dialogs/dialog_pad_properties.cpp

@@ -1679,6 +1679,9 @@ void DIALOG_PAD_PROPERTIES::updatePadSizeControls()
     }
 
     m_sizeXLabel->GetParent()->Layout();
+    resetSize();
+    Layout();
+    m_MainSizer->Fit( this );
 }