e2e: add OIDC Provider test against grafana, more formatting, minor bug fixes

passbook/providers/oidc/claims.py

@@ -10,5 +10,5 @@ def userinfo(claims: Dict[str, Any], user: User) -> Dict[str, Any]:
     claims["given_name"] = user.name
     claims["family_name"] = user.name
     claims["email"] = user.email
-
+    claims["preferred_username"] = user.username
     return claims

passbook/providers/oidc/views.py

@@ -61,7 +61,7 @@ class AuthorizationFlowInitView(AccessMixin, LoginRequiredMixin, View):
                 PLAN_CONTEXT_PARAMS: endpoint.params,
             },
         )
-        plan.stages.append(in_memory_stage(OIDCStage))
+        plan.append(in_memory_stage(OIDCStage))
         self.request.session[SESSION_KEY_PLAN] = plan
         return redirect_with_qs(
             "passbook_flows:flow-executor-shell",