Allow to always display the main keyboard instead of number keyboard at number field

An example of a number field is on websites, like the GitHub site when you login you get a code by email (security reasons).

When you click on this number field you have to enter the code. But I don't like it when the number keyboard layout appears as default for number field.

There is no option in the settings that I can use the main keyboard also for number field. Maybe the problem can also be solved if in number keyboard there is a button to switch to main keyboard.

Start by tracing the Android input method's number-field handling and the existing keyboard settings entry points. Determine how number fields select the numeric layout and where a preference could apply. Done means users can choose the main keyboard for number fields, or switch from the numeric layout, with the behavior covered by the relevant tests if they exist.

Written by the indexing model from the issue text.