Description of problem: if export app toast is not cleared by the user and a new one is triggered then old toast download gives 404

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

Steps to Reproduce

1. create an ns and add a deployment
2. export app and wait for it to complete
3. export app again once step 2 is done
4. don't dismiss the final toast or click download

Actual results: can see multiple toast and old toast has download link which gives 404

Expected results: once export CR gets deleted then associated toast should gets dismissed and toast link should not give 404

Reproducibility (Always/Intermittent/Only Once): Always

Build Details: 4.9.0-0.nightly-2021-08-23-224104

Additional info: