Make "Send Invitation" button active by default

[clevermind-me]

In order for the button to become active now you need to press enter after entering the mail. If you do not do this, the button does not become active and it is not intuitively clear why the invitation is not sent.

In other applications, for example, in Gameplan, the button is active by default, this is more convenient for users.

[safwansamsudeen]

Thanks - will fix.