No error screen showing when connection to API fails

[manuelwedler]

Describe the bug

The current version of the WebUI doesn't show the errors screen when it fails to connect to the API. In #573 we introduced a change to the error handling interceptor in order to not handle PFS API errors as client API errors. The problem seems to be this check:

webui/src/app/interceptors/error-handling.interceptor.ts

Line 50 in ddfe17d

error.url.startsWith(this.raidenConfig.api) &&

It seems like it does not match the URL of the Raiden API.

Steps to reproduce

Close the Raiden client while having the WebUI open in the browser.

Expected behavior

Show the error screen.

System

• Raiden: v1.1.1.dev445+g35ef6b589
• WebUI: v1.1.1
• Environment: development
• Network: Görli
• User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:86.0) Gecko/20100101 Firefox/86.0