Can't use `server_name` to select server for login

### Steps to reproduce

1. Install Element on Android.
2. Click "I already have an account".
3. Enter the `server_name` (not the same as `public_baseurl`)
4. Get an error message: "This is not a valid Matrix server address"

### Outcome

#### What did you expect?

The application to resolve the `public_baseurl` by following the `/.well-known/matrix/client` or `server` endpoint.

### Operating system version

Android 11

### Application version and app store

Element/M.SDK version: `1.5.11`, olm version: `3.2.12`

### Homeserver

Synapse 1.73.0

### Will you send logs?

No

### Are you willing to provide a PR?

No

### Additional information

The following is reported back by the federation tester when querying `domain.example` (obviously a placeholder) which seems to report valid information:
```json
{
"WellKnownResult": {
"m.server": "matrix.domain.example:443",
"CacheExpiresAt": 0
},
"DNSResult": {
"SRVSkipped": true,
"SRVCName": "",
"SRVRecords": null,
"SRVError": null,
"Hosts": {
"matrix.domain.example": {
"CName": "matrix.domain.example.",
"Addrs": [
"xxx.xxx.xxx.xxx"
],
"Error": null
}
},
"Addrs": [
"xxx.xxx.xxx.xxx:443"
]
},
"ConnectionReports": {
"xxx.xxx.xxx.xxx:443": {
"Certificates": [
{
"SubjectCommonName": "domain.example",
"IssuerCommonName": "R3",
"SHA256Fingerprint": "some-long-fingerprint-string-1",
"DNSNames": [
"matrix.domain.example",
"domain.example"
]
},
{
"SubjectCommonName": "R3",
"IssuerCommonName": "ISRG Root X1",
"SHA256Fingerprint": "some-long-fingerprint-string-2",
"DNSNames": null
},
{
"SubjectCommonName": "ISRG Root X1",
"IssuerCommonName": "DST Root CA X3",
"SHA256Fingerprint": "some-long-fingerprint-string-2",
"DNSNames": null
}
],
"Cipher": {
"Version": "TLS 1.3",
"CipherSuite": "TLS_AES_256_GCM_SHA384"
},
"Checks": {
"AllChecksOK": true,
"MatchingServerName": true,
"FutureValidUntilTS": true,
"HasEd25519Key": true,
"AllEd25519ChecksOK": true,
"Ed25519Checks": {
"ed25519:a_OgJK": {
"ValidEd25519": true,
"MatchingSignature": true
}
},
"ValidCertificates": true
},
"Errors": [],
"Ed25519VerifyKeys": {
"ed25519:a_OgJK": "some-long-fingerprint-string-4"
},
"Info": {},
"Keys": {
"old_verify_keys": {},
"server_name": "domain.example",
"signatures": {
"domain.example": {
"ed25519:a_OgJK": "some-very-long-signature-string-1"
}
},
"valid_until_ts": 1671286705801,
"verify_keys": {
"ed25519:a_OgJK": {
"key": "some-long-fingerprint-string-4"
}
}
}
}
},
"ConnectionErrors": {},
"Version": {
"name": "Synapse",
"version": "1.73.0"
},
"FederationOK": true
}
```