refactor(web,server): use feature flags for oauth (#3928)

* refactor: oauth to use feature flags

* chore: open api

* chore: e2e test for authorize endpoint

server/test/e2e/oauth.e2e-spec.ts

@@ -0,0 +1,42 @@
+import { AppModule, OAuthController } from '@app/immich';
+import { INestApplication } from '@nestjs/common';
+import { Test, TestingModule } from '@nestjs/testing';
+import request from 'supertest';
+import { errorStub } from '../fixtures';
+import { api, db } from '../test-utils';
+
+describe(`${OAuthController.name} (e2e)`, () => {
+  let app: INestApplication;
+  let server: any;
+
+  beforeAll(async () => {
+    const moduleFixture: TestingModule = await Test.createTestingModule({
+      imports: [AppModule],
+    }).compile();
+
+    app = await moduleFixture.createNestApplication().init();
+    server = app.getHttpServer();
+  });
+
+  beforeEach(async () => {
+    await db.reset();
+    await api.adminSignUp(server);
+  });
+
+  afterAll(async () => {
+    await db.disconnect();
+    await app.close();
+  });
+
+  describe('POST /oauth/authorize', () => {
+    beforeEach(async () => {
+      await db.reset();
+    });
+
+    it(`should throw an error if a redirect uri is not provided`, async () => {
+      const { status, body } = await request(server).post('/oauth/authorize').send({});
+      expect(status).toBe(400);
+      expect(body).toEqual(errorStub.badRequest);
+    });
+  });
+});