Add Delete mutation to linked resources widget

What does this MR do and why?

Related to #230852 (closed)

This MR adds the mutation to the linked resources widget, to delete the linked resources for an incident.

Part 1 of this feature - !92237 (merged)

Part 2 of this feature - !92352 (merged)

Part 3 of this feature - !92880 (merged)

The buttons on the form are non-functional, this MR just adds the delete function to the remove icon (x) on the linked resources list.

Screenshots or screen recordings

Screen_Recording_2022-07-22_at_8.10.10_PM

How to set up and validate locally

1. Follow the steps on !88826 (merged) to add a resource link using GraphQL API.
2. Open the same incident page on the UI.
3. Check the linked resource on the UI and click on the remove button to see it get deleted.

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.

Related to #230852 (closed)