title: Boolean query params are treated as strings and not transformed to boolean datatype
body: <p>I am running into an issue with supertest when a query parameter ({count: false}) is passed NestJS treats it as a string because the dto validation is not being executed.
  test is </p>
  
  <pre><code>      it.only('should NOT return count if count is turned off', async done =&gt; {
      const result = await request(app.getHttpServer())
        .get('/setting/')
        .set('Content-Type', 'application/json')          
        .query({count:false})
        .expect(200)
      done();
    });
  </code></pre>
  
  <p>dto is</p>
  
  <pre><code>export class CollectionQueryDto {
  
    @IsOptional()
    @IsNotEmpty()
    afterId: any;
  
    @IsOptional()
    @IsOptional()
    @Transform((count, obj, type) =&gt;
      obj.count.toLowerCase() === 'true' ? true : false,
    )
    count: boolean;
  
    constructor(partial: Partial&lt;CollectionQueryDto&gt; = {}) {
      Object.assign(this, partial);
    }
  }
  
  </code></pre>
  
  <p>beforeAll is setup as follows</p>
  
  <pre><code>    beforeAll(async () =&gt; {
        const moduleFixture: TestingModule = await Test.createTestingModule({
          imports: [
            SettingModule,
            SortationOrmModule,
            ConfigModule,
            GlobalOrmModule,
          ],
          providers: [SettingService, ConfigService],
        }).compile();
        app = moduleFixture.createNestApplication();
        service = moduleFixture.get&lt;SettingService&gt;(SettingService);
        await app.init();
        const rowsAffected = await loadConfigurationData(
          'TST.loadConfigurationData',
        );
      });
  
  </code></pre>
  
  <p>Main.ts has the validation pipe</p>
  
  <pre><code>  app.useGlobalPipes(
      new ValidationPipe({
        transform: true,
        forbidUnknownValues: true,
        transformOptions: {
          enableImplicitConversion: true,
        },
        exceptionFactory: errors =&gt; new ClassValidationException(errors),
      }),
    );
  </code></pre>
  
  <p>Any help would be appreciated.</p>