Clear method to clear messages

[jtpio]

Problem

Currently consumers of IChatModel need to use the following method to clear all messages:

jupyter-chat/packages/jupyter-chat/src/model.ts

Line 157 in 73512c1

messagesDeleted(index: number, count: number): void;

For example:

this.messagesDeleted(0, this.messages.length);

Proposed Solution

Maybe it could be more convenient if a clear method was exposed?

Additional context

One objection would be that adding a new method increases the API surface.

[brichet]

Thanks @jtpio, that would be useful 👍, indeed.