Fix crash when cancelling fp table setup

The missing OnPgmExit leads to a segfault later if you
cancel the FP table setup when initialising a new config.

Fixes: https://gitlab.com/kicad/code/kicad/-/issues/16525

common/single_top.cpp

@@ -351,6 +351,8 @@ bool PGM_SINGLE_TOP::OnPgmInit()
 
     if( frame == nullptr )
     {
+        // Clean up
+        OnPgmExit();
         return false;
     }