fix(core): Set `sentry.source` attribute to `custom` when calling `span.updateName` on `SentrySpan`#14251

Lms24 merged 5 commits intodevelopgetsentry/sentry-javascript:developfrom

lms/fix-core-source-custom-span-updatenamegetsentry/sentry-javascript:lms/fix-core-source-custom-span-updatenameCopy head branch name to clipboard