Fix blinking empty state on issues dashboard

What does this MR do and why?

This MR removes debounce from the GraphQL queries on issues dashboard page. This results in removing a briefly visible (200ms) Sorry, your filter produced no results screen before showing cached labels.

Screenshots or screen recordings

Before	After
before	after

How to set up and validate locally

1. Open issues dashboard page: http://127.0.0.1:3000/dashboard/issues?assignee_username=root
2. Make sure page starts loading immediately, without brief "No results" screen
3. Click the invite members button.

MR acceptance checklist

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