"Edit homeserver host" modal window does nothing on "Continue" action if server is slow to respond

### Steps to reproduce

1. Press to "Edit" in "Sign In" form to change the homeserver url.
2. Type url of some homeserver, that is responding slowly.
3. Press "Continue" button.

### Outcome

#### What did you expect?
I expect to see some spinner or other animation, that Element is checking something.

#### What happened instead?
Nothing happened, as if I don't even click on "Continue" button. But after some timeout label color changes to red, but without any explanation:

### Operating system

Ubuntu

### Browser information

Firefox 94

### URL for webapp

develop.element.io

### Application version

Element version: 0a5adedbc12f-react-68ac5785770d-js-4e9fe8f53fd2 Olm version: 3.2.3

### Homeserver

ru-matrix.org

### Will you send logs?

No