Fix exception will thrown if token belongs to first party clients

[alshf89]

I made a pull request for issue #691.

So when someone passes a token in their request which belongs to first party clients (such as Password Credentials), our middlewares will throw an Illuminate\Auth\AuthenticationException Exception.

So only those who have issued access token with Client Credentials grant type can go through CheckClientCredential & CheckClientCredentialForAnyScope Middlewares.

[alvirbismonte]

Hi @JuanDMeGon ,

I believe the reason behind this change is because they separated the authentication between the user credentials(password grant type) and client credentials (client grant type). As mentioned from API Authentication (Passport) which states that

client credentials grant is suitable for machine-to-machine authentication

[JuanDMeGon]

Thanks. I think it is not correct. The purpose of the client credentials grant is to validate the access to the API from valid clients when there is not User data involved.
Basically, it is what stands in OAuth2 official site:
"The Client Credentials grant is used when applications request an access token to access their own resources, not on behalf of a user." Source
I opened an issue (#1125) to discuss this, maybe you would like to comment on your opinion on this.
Best wishes :)