ref(ci): switch to internal github app (sentry-release-bot) (#123034)

BUMP_SENTRY_TOKEN is a getsentry-bot legacy PAT and it'd be preferable
to switch to our internal github apps and mint tokens as needed

also choosing to use `sentry-release-bot` instead of `getsantry`
(SENTRY_INTERNAL_APP_ID) for the x-repository stuff since it already has
bypass actor in (get)sentry with contents:write