deps: remove duplicated postmortem metadata entry

Signed-off-by: Matheus Marchini <mmarchini@netflix.com>

PR-URL: https://github.com/nodejs/node/pull/32521
Refs: https://github.com/v8/v8/compare/8.1.307.20...8.1.307.26


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>