refactor: remove unnecessary assertion

Author: noritaka1166

src/android.ts

@@ -19,7 +19,7 @@ export async function androidPortForward(
  systemPort: number,
  devicePort: number,
 ) {
- await adb.forwardPort(systemPort!, devicePort);
+ await adb.forwardPort(systemPort, devicePort);
 }
 
 export async function androidRemovePortForward(adb: ADB, systemPort: number) {

src/utils.ts

@@ -161,13 +161,13 @@ export async function fetchFlutterServerPort(
  `Checking if flutter server is running on port ${systemPort || devicePort} for simulator with id ${udid}`,
  );
  await waitForFlutterServer.bind(this)(
- (systemPort || devicePort)!,
+ (systemPort || devicePort),
  packageName,
  );
  this.log.info(
  `Flutter server is successfully running on port ${systemPort || devicePort}`,
  );
- return (systemPort || devicePort)!;
+ return (systemPort || devicePort);
  } catch (e) {
  return null;
  }
@@ -337,7 +337,7 @@ function readManifest(): StringRecord {
  node.getModuleRootSync(
  'appium-flutter-integration-driver',
  __filename,
- )!,
+ ),
  'package.json',
  ),
  { encoding: 'utf8' },