Resolve "updateEndpoint undefined on Issue page"

Closes #40715

See merge request gitlab-org/gitlab-ce!15698

(cherry picked from commit be8ca260)

3e9e773c Remove unused updateUrl and updateEndpoint
0ce9215e Revert updateUrl and updateEndpoint removal and instead pass updateEndpoint…
15b2fc3b simplify props for issue_show app root
4d86f05a Add changelog entry