Show failure message when task list fails to load

What does this MR do and why?

Shows GlAlert with error message when task items fail to load within issues.

Screenshots or screen recordings

The generic error message that we show is;

Something went wrong when fetching the items list. Please refresh this page.

How to set up and validate locally

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

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

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