[api] Use FixedVector const references for service array arguments (#11546)

esphome/cpp_types.py

@@ -23,6 +23,7 @@ size_t = global_ns.namespace("size_t")
 const_char_ptr = global_ns.namespace("const char *")
 NAN = global_ns.namespace("NAN")
 esphome_ns = global_ns  # using namespace esphome;
+FixedVector = esphome_ns.class_("FixedVector")
 App = esphome_ns.App
 EntityBase = esphome_ns.class_("EntityBase")
 Component = esphome_ns.class_("Component")