Call button and Send button are in the same place

On iOS after one types a message, the Send button appears in the place where the Call button was. This makes it easy to misclick on the Call button if the user accidentally presses Send twice. This is even worse if a call is connected, because that hangs up the call. I think we should be given the choice to move the Call button somewhere else.

Start by reproducing the button overlap on iOS while composing a message and during an active call, then trace the message composer and call-control entry points. Define the placement choice and verify that sending twice cannot trigger or hang up a call; no specific file or test is named in the issue.

Written by the indexing model from the issue text.