Update input state after inviting the client.

[sethhrbek]

Prior to sending invite:

1. Disable the button (isDisabled={} in chakra button component) if the email is not valid. Only enable the button once the email is valid.

When invite is sent to client (after clicking button):

1. use the isLoading state in the Chakra button component to indicate a request is pending (this will disable the button after being clicked)
2. If request is successful, clear the input value (remove the email)