feat(core): Remove getGlobalHub export (#11565)

Just noticed we export this API from core but it's not used in packages
outside of `@sentry/core` (anymore?). Let's remove it while we can.

Author: Lms24

packages/core/src/index.ts

@@ -34,7 +34,6 @@ export {
   getCurrentHub,
   // eslint-disable-next-line deprecation/deprecation
   Hub,
-  getGlobalHub,
   getDefaultCurrentScope,
   getDefaultIsolationScope,
 } from './hub';