Make sure the hierarchy navigation history iterator is valid before
attempting to remove an entry from the history list.
Fix an undetected crash where two undo entries were created when drawing
a new sheet. The first entry was sheet properties entry and the second
was for the drawing the new sheet. The second undo would cause a crash
because the sheet no longer existed for the sheet properties commit.
Remove consecutive duplicate hierarchy navigator history history entries.
Navigating to the same path multiple times doesn't really make a lot of
sense.
Don't rebuild the hierarchy twice when drawing new sheets. This is handled
when pushing a commit.
Fixes https://gitlab.com/kicad/code/kicad/-/issues/19358
Wayne Stambaugh
846a346d21