feat: added get initialization status

zh_espnow.c

@@ -516,4 +516,9 @@ void zh_espnow_reset_stats(void)
     _stats.sent_fail = 0;
     _stats.received = 0;
     ZH_ESPNOW_LOGI("ESP-NOW statistic reset successfully.");
+}
+
+bool zh_espnow_is_initialized(void)
+{
+    return _is_initialized;
 }