Allow for "camera" button in Message Bar

[rebeccaalpert]

Guillaume Moutier asked for a "camera" button for the Message Bar, for functions separate from attach.

The chatbot team wants to allow for further customization of the attach menu and use it for additional actions like camera buttons. We can allow for changing the tooltip/icon, add a demo, and potentially design guidelines. The concern with custom buttons from design is that the number can grow too large - want to steer people towards a solution that allows for extra actions. Design suggested a + icon, but it can be made customizable as well.

[guimou]

As an example, implementation here: https://github.com/rh-aiservices-bu/multimodal-chatbot/blob/main/app/frontend/src/app/components/Chat/MessageBarCamera.tsx

[rebeccaalpert]

We talked about this on the chatbot call; the team wants to allow for further customization of the attach menu and use it for additional actions like camera buttons. We can allow for changing the tooltip/icon, add a demo, and potentially design guidelines. The concern with custom buttons from design is that the number can grow too large - want to steer people towards a solution that allows for extra actions. Design suggested a + icon, but it can be made customizable as well. Will update this issue to reflect that.

[rebeccaalpert]

Should be fixed by #751!