fix: cast TextInput state to an integer when using integer()

[lazerg]

Description

Fixes #20364

TextInput::make('quantity')->integer() used the same state cast as numeric(), which runs floatval(). So getState() gave back 1234.0 instead of 1234. Saving to a model hid this, since the model cast corrected the type, but data read straight out of a schema (an action's $data, for example) kept the float.

integer() now tells NumberStateCast to use intval() instead.

Functional changes

• Code style has been fixed by running the composer cs command.
• Changes have been tested to not break existing functionality.
• Documentation is up-to-date.