Add dummy input field to settings to make trying out your preferences easier

[realpixelcode]

Is your feature request related to a problem? Please describe.

Not an actual problem.

Describe the solution you'd like

Add a text input field that doesn't do anything, to the settings, for example sticked to the bottom.

Use case

When you change your preferences, you wouldn't have to leave the settings anymore to try out the keyboard.

Describe alternatives you've considered
None

Additional context

Here's FlorisBoard's implementation:

[Helium314]

For now you can try it in language settings and in color settings.
Btw FlorisBoard test field causes very weird bugs at times, especially when using space bar to move the cursor.

[ghost]

Instead of input field at the bottom of the screen, what about some floating button in every settings screen, which will redirect you to a "test screen" with text area where you will try the setting. Once the testing is done, you will press back on system's navigagion bar or back button on test screen, which will return you to settings screen.

Floating button will appear after setting change and disappear when leaving setting / subsetting screen. Alternatively, button will be always present and only active / inactive state will change.

[KaKi87]

I strongly prefer an input field at the bottom of the screen, avoiding going back and forth.

[GL513]

Ditto to this issue

[Helium314]

Removing label as it will be part of #1109