Impossible to Log In unless Homeserver has Open Registration

### Steps to reproduce

When I created a matrix account for my friend on our synapse homeserver @ matrix.cyberia.club, and told him to enter the homeserver URL into element, It just threw up a "registration is disabled" toast and would not let him log in with the username and password that he chose.

Maybe we are just not "galaxy brained" enough, but we could not figure out any way past it.

### Outcome

#### What did you expect?

I expected that a user who already knows thier username and password would be able to log into their account on a homeserver that does not have open registration.

#### What happened instead?

User was blocked from using Element.

### Your phone model

N/A

### Operating system version

N/A

### Application version and app store

Freshly downloaded from google play on March 7 2025

### Homeserver

{"server":{"name":"Synapse","version":"1.124.0"}}

### Will you send logs?

No

### Are you willing to provide a PR?

No