Closes #18991

Description

Some self-hosted repositories may not have a valid SSL certificate and that could be ok. Git offers the http.sslverify option to disable SSL verification for all git operations, or only for git operations on certain hosts. We could use that here, but we don't want to duplicate that logic to match domains, order of preference of different options...

Instead, we'll just reject all requests to /meta that fail SSL verification. The reasoning for that is:

1. This request is only used to find out if the host is a GitHub Enterprise instance. It's ok if this fails for whatever reason for self-hosted repositories, since returning undefined in this function means "we don't know if this is a GitHub host or not".
2. We're want to assume (for now, at least) that GitHub Enterprise instances are always running with a valid SSL certificate.

If we used fetch for this, in the case of an invalid SSL certificate Electron would dispatch a 'certificate-error' event on the main process that we must handle to allow the request to finish (in this case, by rejecting it). However, we're using https.request here, so we don't need to handle that and can get rid of the complexity of dealing with stuff happening on the main process.

Release notes

Notes: [Fixed] Don't show certificate error when pushing to self-hosted repositories