[2] Handle long reponses for external address queries

While working on the Withdraw/Deposit modals I came across a slight issue where the gateway may be very slow at returning an address or to validate an address for the user.

## Current workings
Today the app will simply wait until it receives the data. During this time there is a "loading" sign, but it can go on indefinitely if nothing is returned.

## Proposed workings
I propose that after certain amount of time, the app informs the user that "this takes longer than expected"

Start by tracing the Withdraw and Deposit modals and the external address query handling, then inspect how the existing loading state is presented. Define the timeout behavior and verify that slow responses show the proposed message while normal responses continue to work.

Written by the indexing model from the issue text.