Send Email Alert : Validation error , user is able to validate Invalid email address in sender and recipients

Send Email Alert : Validation error , user is able to validate Invalid email address in sender and recipients field e.g; abnvc for those fields is being validated.

Steps: 

1. Launch the Latest version of CDAP .

2. Create a sample pipeline.

3. Click on the configure tab.

4. Select pipeline alert.

5. Click on + button.

6. Click on email alert.

7. Enter the invalid test data in the sender and recipients field.

Expected Result : Should throw a validation error.

Actual Result: user is validating invalid  test data.