Focus back to the main window after dialog

Mouse actions would focus the window but we explicitly set it here to
allow keyboard shortcuts

Fixes https://gitlab.com/kicad/code/kicad/-/issues/15603

(cherry picked from commit b2ef620ea6)

common/dialog_shim.cpp

@@ -282,6 +282,9 @@ bool DIALOG_SHIM::Show( bool show )
         ret = wxDialog::Show( show );
     }
 
+    if( m_parent )
+        m_parent->SetFocus();
+
     return ret;
 }
 
@@ -483,6 +486,9 @@ int DIALOG_SHIM::ShowQuasiModal()
 
     m_qmodal_showing = false;
 
+    if( parent )
+        parent->SetFocus();
+
     return GetReturnCode();
 }