qto.py: Make nan/inf magnitude checks accept uncertainties

[doronbehar]

• Closes to_compact is broken for Measurements and for Quantitys with uncertainties #2044 (insert issue number)
• Executed ruff format on the modified files, and checked that CI on my fork is green.
• The change is fully covered by automated unit tests
• Documented in docs/ as appropriate
• Added an entry to the CHANGES file

[andrewgsavage]

merged this #2093

[doronbehar]

Thanks.