This might be the reason behind wger-project/wger#2028 since depending on the routine
the server could get hammered with requests and one (or other unrelated ones) fail.
Even if this is not the case, being a bit more reserved here is still a good idea.
We now use TextInputType.numberWithOptions(decimal: true) which seems to have
a more consistent behaviour under android and iOS. Also, we now use NumberFormat
to parse the inputs according to the user's locale.
