Fixed "Time to SLA" column sort UI behavior

What does this MR do and why?

This fixes the UI for "Time to SLA" column wherein the hover state and column direction does not behave correctly.

Issue: #383877

Screenshots or screen recordings

Before	After
Screen_Recording_2023-10-05_at_7.52.40_AM	Screen_Recording_2023-10-07_at_3.53.18_PM

How to set up and validate locally

Prerequisite

• Enable Ultimate tier for your account
• Enable SLA timer for the project (Settings > Monitor > Incidents > Incidents settings)

Steps

• In a project, go to the incidents list (Monitor > Incidents)
• Hover the table column (specifically "Time to SLA") and verify that it should have the same hover state and column sort behavior along the other sortable columns (eg: "Status", "Severity")

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.