feat: turns on self-signed JWT feature flag (#335)

- [ ] Regenerate this pull request now.

PiperOrigin-RevId: 392067151

Source-Link: googleapis/googleapis@06345f7

Source-Link: googleapis/googleapis-gen@95882b3

packages/google-cloud-phishingprotection/src/v1beta1/phishing_protection_service_v1_beta1_client.ts

@@ -123,6 +123,12 @@ export class PhishingProtectionServiceV1Beta1Client {
     // Save the auth object to the client, for use by other methods.
     this.auth = this._gaxGrpc.auth as gax.GoogleAuth;
 
+    // Set useJWTAccessWithScope on the auth object.
+    this.auth.useJWTAccessWithScope = true;
+
+    // Set defaultServicePath on the auth object.
+    this.auth.defaultServicePath = staticMembers.servicePath;
+
     // Set the default scopes in auth client if needed.
     if (servicePath === staticMembers.servicePath) {
       this.auth.defaultScopes = staticMembers.scopes;