[Impeller] Don't create a redundant typography context. (#163513)

This was a typo that caused a typography context to be created, its
validity checked, but the context not actually used. Instead returning a
new one.

No change in functionality.

engine/src/flutter/impeller/toolkit/interop/impeller.cc

@@ -1264,7 +1264,7 @@ ImpellerTypographyContext ImpellerTypographyContextNew() {
     VALIDATION_LOG << "Could not create typography context.";
     return nullptr;
   }
-  return Create<TypographyContext>().Leak();
+  return context.Leak();
 }
 
 IMPELLER_EXTERN_C