Fix Flake8 error

Signed-off-by: M Q <mingmelvinq@nvidia.com>

Author: MMelQin

examples/apps/simple_imaging_app/gaussian_operator.py

@@ -9,8 +9,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from numpy import uint8
-
 import monai.deploy.core as md
 from monai.deploy.core import DataPath, ExecutionContext, Image, InputContext, IOType, Operator, OutputContext