Footprint chooser frame: fix crash in COMMON_TOOLS::ResetLocalCoords()

The crash was due to a null pointer thta can happens in Footprint chooser,
frame, when hit the space bar if the canvas showing the Fp has the focus.

Fixes https://gitlab.com/kicad/code/kicad/-/issues/20780

(cherry picked from commit 34e49758d0)

common/tool/common_tools.cpp

@@ -679,6 +679,9 @@ int COMMON_TOOLS::TogglePolarCoords( const TOOL_EVENT& aEvent )
 
 int COMMON_TOOLS::ResetLocalCoords( const TOOL_EVENT& aEvent )
 {
+    if( !m_frame->GetScreen() )     // Can happen in footprint chooser frame
+        return 0;
+
     const KIGFX::VC_SETTINGS& vcSettings = m_toolMgr->GetCurrentToolVC();
 
     // Use either the active tool forced cursor position or the general settings