Fix warning filter in normalise_func.py

[sargreal]

Description

• Adjust the warning filter in normalise_func.py to only handle RuntimeWarning, which is the Warning catched later. All other Warnings can be handled by the user of the library as they wish
• Fixes Incompatibility with numpy 2.4 due to UserWarning incorrectly handled #371
• This allows usage of this library and the tutorials with numpy 2.4 (probably also since 2.0)

Implemented changes

• Insert a description of the changes implemented in the pull request.
  • Make warning filter only error on RuntimeWarning

Minimum acceptance criteria

• Verify that there are no other places where this warning filtering is done
• @annahedstroem