AuthN: Support reloading SSO config after the sso settings have changed (#80734)

* Add AuthNSvc reload handling

* Working, need to add test

* Remove commented out code

* Add Reload implementation to connectors

* Align and add tests, refactor

* Add more tests, linting

* Add extra checks + tests to oauth client

* Clean up based on reviews

* Move config instantiation into newSocialBase

* Use specific error

pkg/services/ssosettings/api/api_test.go

@@ -134,7 +134,7 @@ func TestSSOSettingsAPI_Update(t *testing.T) {
 
 			service := ssosettingstests.NewMockService(t)
 			if tt.expectedServiceCall {
-				service.On("Upsert", mock.Anything, settings).Return(tt.expectedError).Once()
+				service.On("Upsert", mock.Anything, &settings).Return(tt.expectedError).Once()
 			}
 			server := setupTests(t, service)