Don't prune already-added items from the COMMIT.

We perform undo/redo backwards from each other specificially to allow
multiple entries (for instance, a wire is modified and then deleted).

This bus is almost certainly in 7.0 as well, but it comes up mostly
in schematics where 7.0 doesn't use COMMIT.  It's also possible that it
will cause unwanted effects in some cases, so I'm leaving it only in
master.

Fixes https://gitlab.com/kicad/code/kicad/-/issues/15032

common/commit.cpp

@@ -151,14 +151,6 @@ void COMMIT::makeEntry( EDA_ITEM* aItem, CHANGE_TYPE aType, EDA_ITEM* aCopy, BAS
     // Expect an item copy if it is going to be modified
     wxASSERT( !!aCopy == ( ( aType & CHT_TYPE ) == CHT_MODIFY ) );
 
-    if( m_changedItems.find( aItem ) != m_changedItems.end() )
-    {
-        alg::delete_if( m_changes, [aItem, aScreen]( const COMMIT_LINE& aEnt )
-                                   {
-                                       return aEnt.m_item == aItem && aEnt.m_screen == aScreen;
-                                   } );
-    }
-
     COMMIT_LINE ent;
 
     ent.m_item = aItem;