Jar file upload flow should prevent the user from closing the window while its in progess.

Description of problem:  

While JAR file is uploading, the user is able to close the browser, This causes the workload to fail. 

Prerequisites (if any, like setup, operators/versions):

Steps to Reproduce

1.  Click Upload Jar in Add flow.
2. Browse and add the jar file and click on create
3. While the JAR file is uploading, try to close the broswer.

Actual results: 

User is able to close the broswer.

Expected results: 

User should not be able to close the browser when upload is in progress.

Reproducibility (Always/Intermittent/Only Once):  

Always.

Build Details:  

4.9.0-0.nightly-2021-08-22-005117