Remove autocomplete re-export from directives to break circular dependency

- Removed re-export of IgxAutocompleteDirective from directives
- Re-exporting from drop-down was creating circular dependency
- This is a breaking change: users must import autocomplete from 'igniteui-angular/drop-down'
- Main entry point still re-exports for backwards compatibility
- ng update migration will handle this change for users

Breaking change necessary to eliminate circular dependency

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

Author: Copilot

projects/igniteui-angular/directives/src/public_api.ts

@@ -1,6 +1,7 @@
 // Directives
-// Note: Autocomplete moved to drop-down entry point. Re-exported here for backwards compatibility.
-export { IgxAutocompleteDirective } from 'igniteui-angular/drop-down';
+// Note: Autocomplete moved to drop-down entry point in v21.0.0
+// Users should now import from 'igniteui-angular/drop-down' instead
+// Removed re-export to avoid circular dependency
 export * from './directives/button/button.directive';
 export * from './directives/divider/divider.directive';
 export * from './directives/drag-drop/public_api';