fix: clear pending exception before rejecting a builtin dynamic import

The dynamic-import builtin failure path rejected the resolver while the
exception caught from GetModule was still pending on the isolate; V8 API
calls with a pending exception are unsafe. The non-builtin path below
already resets before rejecting.

Reported by review on #1992.

Author: edusperoni

test-app/runtime/src/main/cpp/ModuleInternalCallbacks.cpp

@@ -888,6 +888,8 @@ v8::MaybeLocal<v8::Promise> ImportModuleDynamicallyCallback(
                     tc.HasCaught() ? tc.Exception()
                                    : v8::Exception::Error(ArgConverter::ConvertToV8String(
                                              isolate, NsBuiltinModules::NotFoundMessage(spec)));
+            // Reject must not run with the exception still pending on the isolate.
+            tc.Reset();
             resolver->Reject(context, error).FromMaybe(false);
         }
         return scope.Escape(resolver->GetPromise());