Add retry on exception to check vuln report is loaded

What does this MR do and why?

This MR tries to address the issue found here

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

WEBDRIVER_HEADLESS=false GITLAB_ADMIN_PASSWORD="xxxx" GITLAB_QA_ACCESS_TOKEN=xxxxx GITLAB_PASSWORD="xxxx" QA_DEBUG=true QA_GITLAB_URL=http://192.168.1.105:3000 bundle exec rspec ./qa/specs/features/ee/browser_ui/13_secure/vulnerability_management_spec.rb:62

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.