Support multiple GitHub orgs in a single GitHub Access entitlement

Currently, a GitHub Access entitlement only lists repositories from one org, even when the Dodo Payments GitHub App is installed on multiple orgs. Merchants have to disconnect, reconnect, and create a separate entitlement per org as a workaround. The entitlement should list repositories from all connected orgs (or provide an org selector), so repos from multiple orgs can be granted in a single entitlement.