wxGUI/main_window: fix displaying save workspace dialog before close workspace action (OSGeo#6387)

When closing workspace action is triggered via main window menu
File -> Workspace -> Close

Author: tmszi

gui/wxpython/main_window/frame.py

@@ -1710,7 +1710,8 @@ def OnWorkspaceSaveAs(self, event=None):
 
     def OnWorkspaceClose(self, event=None):
         """Close file with workspace definition"""
-        self.workspace_manager.Close()
+        if self.workspace_manager.CanClosePage(caption=_("Close workspace")):
+            self.workspace_manager.Close()
 
     def OnDisplayClose(self, event=None):
         """Close current map display window"""