T3062

Depends on D13503

This diff prevents alias registrations in the event of the alias-server being down.

Users can still view their registered aliases and send XEC to aliases in their existing cache.

• change currency.aliasSettings.aliasServerBaseUrl in ticker.js to an incorrect url
• enable alias in ticker.js
• npm start
• note the getAliasServerState exception and ensure the existing aliases in cache have not been wiped out.
• navigate to Alias.js and ensure the registered aliases list is still intact with an exception thrown for getPendingAliases
• verify in localForage's cashtabCache.aliasCache object is still intact
• attempt to register a new alias and ensure the Unable to connect to alias server, please try again later error notification is displayed
• attempt to register an alias already registered in cache and ensure the same alias-server error is displayed
• navigate to Send.js and SendToken.js and ensure aliases in cache are still resolving to their corresponding addresses
• wait for a new block to be found and ensure this does not wipe out the aliases in cache either
• revert currency.aliasSettings.aliasServerBaseUrl to the original url and ensure no issues with onchain alias count polling and alias registrations are enabled
• disable alias in ticker.js and ensure no regression to existing functions