Admin: Hard to enter floating point numbers in "Unit conversion factor" field

[marcelgerber]

Description

In the admin, when editing a chart's dimensions, entering a number like 0.0001 for the unit conversion factor is unnecessarily hard.

The text fields resets any number that parseFloat doesn't accept, but some of these numbers - like 1. - are necessarily a byproduct of entering a floating point number.

Video

https://user-images.githubusercontent.com/2641501/167196140-6904e51f-1514-4edd-a798-def21d44f2bb.mp4

Additional context

Possible workarounds:

• Do as I did in the video, going 11 -> 1.1 -> .1 -> 0.1 -> 0.0001.
• Paste in the full number