fix(runtime): remove synthetic default import (#4066)

Co-authored-by: Hanric <[email protected]>

Author: jabrks

.changeset/old-buttons-hope.md

@@ -0,0 +1,5 @@
+---
+'@module-federation/runtime': patch
+---
+
+Remove synthetic default import.

packages/runtime/src/core.ts

@@ -1,4 +1,4 @@
-import runtimeCore from '@module-federation/runtime-core';
+import * as runtimeCore from '@module-federation/runtime-core';
 
 export * from '@module-federation/runtime-core';