deps: V8: bump v8_embedder_string for 0e21c1e6

0e21c1e6 has landed without a proper
v8_embedder_string bump, this is a follow-up fix.

PR-URL: https://github.com/nodejs/node/pull/31096
Refs: https://github.com/nodejs/node/commit/0e21c1e637bf6d844473d09dca3508f2bf547b89
Refs: https://github.com/nodejs/node/pull/31007


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Myles Borins <myles.borins@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>