Allow TextInputHandler to expose a type to trigger multiline input or single line input

[TerminalFi]

Problem description

In some scenarios I want to allow the TextInputHandler to accept multiline input vs a single line. A few scenarios where this come into play

1. Copilot Chat without affecting user groups or layouts. Just open a prompt in the input handler then stream response using the preview functio
2. Prompt user for a JSON payload or multi line snippet

Preferred solution

Extend the TextInputHandler to include a function like the below or accept a optional argument

def input_type(self) -> Literal['single', 'multiline']:
    return 'single'

Alternatives

None

Additional Information

No response