Prevent double clicking submit buttons

[moul]

When creating a new conversation, clicking on the submit button triggers the creation in background (long task), it's easy (and unblocked) to click multiple times on the button by thinking we missed it first

For unary calls, we should gray out clicked buttons while having a response

[90dy]

We should do it for all buttons, there is the same behavior for button with no unary calls if they take time (maybe caused by react-navigation implementation)