Wrong pop-up message for incorrect user or password, claiming server issue, at least when using Dendrite server

### Steps to reproduce

1. Where are you starting? What can you see?
When trying to login/sign-in to Dendrite server with wrong user or wrong password you get a popup saying:

Error
"Sorry, this server isn't accepting new accounts."

On the Desktop Element app, you get accurate:
"Incorrect username and/or password."

### Outcome

#### What did you expect?
Get error like on Desktop Element app when entering wrong user or password, ie:
**"Incorrect username and/or password."**

#### What happened instead?
Got misleading pop-up message:
Error
**"Sorry, this server isn't accepting new accounts."**

### Your phone model

Samsung Note 9

### Operating system version

Android 8.1

### Application version and app store

Element 1.4.16 Matrix sdk 1.4.16 olm 3.2.10

### Homeserver

Dendrite version 0.8.6

### Will you send logs?

No