[fidl] Migrate fidl::Array to std::array

TEST=CQ

Change-Id: If3ab163f64bb6fe4aca5a273269516f85081e039
diff --git a/runtime/dart/utils/handle_exception.cc b/runtime/dart/utils/handle_exception.cc
index bb81e1e..0d05808 100644
--- a/runtime/dart/utils/handle_exception.cc
+++ b/runtime/dart/utils/handle_exception.cc
@@ -39,7 +39,7 @@
 }
 
 template <typename T, size_t N>
-void CopyToArray(const std::string& s, fidl::Array<T, N>* arr) {
+void CopyToArray(const std::string& s, std::array<T, N>* arr) {
   const size_t max_size = arr->size();
   auto end = s.end();
   if (s.size() > max_size) {