Changing shortcuts in Welcome Screen requires restart to take effect

Steps to reproduce:

• open Inkscape
• Change the shortcuts to ACD Systems Canvas
• Hit save, Thanks, then Load
• Ctrl+Shift+P still opens preferences dialog
• On restart it does not

What happened?

• Despite preferences showing ACD Systems Canvas as the shortcuts file, Inkscape shortcuts are loaded

What should have happened?

• Similar behaviour to if you switch shortcut file in Preferences (it immediately takes effect).
• Ideally the displayed shortcut hints are updated too, but that is a separate issue.

Version Info:

• Inkscape 1.1-dev (17927dee, 2020-12-18) Linux Mint 20