gnucash stable: Do a better job of including the -py3 option only for swig 4.1

[Geert Janssens]

Updated	 via  https://github.com/Gnucash/gnucash/commit/b9eb550b (commit)
	from  https://github.com/Gnucash/gnucash/commit/cbf89a73 (commit)



commit b9eb550b9a9a2ff0a5e926debb1bee5a073a5319
Author: Geert Janssens <geert at kobaltwit.be>
Date:   Thu Feb 22 11:13:59 2024 +0100

    Do a better job of including the -py3 option only for swig 4.1
    
    The previous attempt broke builds with swig older than 4.1



Summary of changes:
 common/cmake_modules/GncAddSwigCommand.cmake | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)