[UX]: Send by Enter in the model chat

[jvstme]

Current

In the model chat, the only way to send the message is by clicking "Send". Pressing "Enter" inserts a new line.

Proposed

As in most desktop chat apps, send the message when "Enter" is pressed. Insert a new line when "Shift+Enter" or "Ctrl+Enter" is pressed.

[github-actions]

This issue is stale because it has been open for 30 days with no activity.

[jvstme]

@olgenn, sorry, could we insert a new line on Shift+Enter too, not only Ctrl+Enter? Both these combinations are common, so if we support both users won't have to guess which one to use

[jvstme]

Thanks for implementing the current version anyway, chatting is much more convenient already