`gh auth login` hangs when `config.yml` is read-only, potentially producing an "auth schism"

### Describe the bug

When `config.yml` is read-only, `gh auth login` hangs indefinitely after having stored the token in secure storage and printing `✓ Authentication complete.` This can cause some confusion for users, as described in the linked discussion below.

### Steps to reproduce the behavior

* https://github.com/cli/cli/discussions/8347#discussioncomment-7601505

### Expected vs actual behavior

* No hangs, but a warning message printed to the console and continue with the process (e.g. by trying to write `hosts.yml`)
* Maybe a more consistent behavior of `gh`, as some parts of the CLI claim authentication is done while others ask for credentials.

### Logs

None.