Enable Graph Explorer with an access token or Service Principal integration

Is your feature request related to a problem? Please describe.
When testing API calls, it is often necessary to observe the results of application permissions, not just delegated. Logging into Graph Explorer using a user principal limits all API calls to delegated permissions.

Describe the solution you'd like
Either (a) allow us to obtain our own access token from a service principal, using whatever authentication mechanism has been setup (secret, cert, etc), and add that to our Graph Explorer session. Or, (b), allow us to put in a service principal appid, secret, and tenantid.

With either of these, the option to obtain JIT consent would be obviated - the SP has permission to call the api, or not. If a permission is needed, it's up to the tester/developer to go add that permission to the registration and re-consent.

Describe alternatives you've considered
The only other way to test here is to use something like Postman, which is what I currently do. This isn't as convenient.

Additional context
Add any other context or screenshots about the feature request here.

Start by reading Graph Explorer's existing authentication and session flow, then compare the two proposed approaches: importing a service-principal token or collecting service-principal credentials. Done means Graph Explorer can test application-permission calls without delegated user login, while preserving appropriate consent and permission behavior.