Summary

This PR implements the "is_exported" query in the SemanticModel.
It will be first used by the noUnusedVariables lint rule (#2979) to avoid false flags like

error[[js/noUnusedVariables](https://rome.tools/docs/lint/rules/noUnusedVariables/)]: This function is unused.
  ┌─ main.js:1:17
  │
1 │ export function f() {

Test Plan

>  cargo test -p rome_js_semantic -- ok_semantic_model_is_exported