Access Control: Allow org admins to invite new users (#52894)

* allow org admins to invite new users to Grafana

* doc updates

* fix test

pkg/api/org_users_test.go

@@ -650,7 +650,7 @@ func TestOrgUsersAPIEndpointWithSetPerms_AccessControl(t *testing.T) {
 			desc:         "org viewer with the correct permissions can invite a user as a viewer in his org",
 			url:          "/api/org/invites",
 			method:       http.MethodPost,
-			permissions:  []accesscontrol.Permission{{Action: accesscontrol.ActionUsersCreate}},
+			permissions:  []accesscontrol.Permission{{Action: accesscontrol.ActionOrgUsersAdd, Scope: accesscontrol.ScopeUsersAll}},
 			input:        `{"loginOrEmail": "newUserEmail@test.com", "sendEmail": false, "role": "` + string(models.ROLE_VIEWER) + `"}`,
 		},
 		{