Freeze GUI as well to prevent wx updates

The tree model may get updated by a redraw, so we need to freeze both
the model and the view while updating

Fixes https://gitlab.com/kicad/code/kicad/issues/5872

eeschema/libedit/lib_edit_frame.cpp

@@ -519,6 +519,7 @@ bool LIB_EDIT_FRAME::IsSearchTreeShown()
 
 void LIB_EDIT_FRAME::FreezeSearchTree()
 {
+    m_treePane->Freeze();
     m_libMgr->GetAdapter()->Freeze();
 }
 
@@ -526,6 +527,7 @@ void LIB_EDIT_FRAME::FreezeSearchTree()
 void LIB_EDIT_FRAME::ThawSearchTree()
 {
     m_libMgr->GetAdapter()->Thaw();
+    m_treePane->Thaw();
 }