uni.getConnectedBluetoothDevices IOS 空

**问题描述**
uni.getConnectedBluetoothDevices IOS 空

**复现步骤**
[复现问题的步骤]
```
getBluetoothDevices() {
console.log("获取蓝牙设备");
uni.getBluetoothDevices({
success: res => {
console.log('获取蓝牙设备成功:' + res.errMsg);
console.log('dddd',res)
}
});

uni.getConnectedBluetoothDevices({
services: ["00001812-0000-1000-8000-***********", "00001812-0000-1000-8000-***********"], //
success(res) {
console.log('bbbb', res)
},
fail(res) {
console.log('cccc', res)
}
});
}
```

**预期结果**
[使用简洁清晰的语言描述你希望生效的预期结果]

**实际结果**
[这里请贴上你的报错截图或文字]

**系统信息:**
- 发行平台: [5+App]
- 操作系统 [如 iOS 14.0]
- HBuilderX版本 [HBuilderX 2.8.13.20200927]
- 设备信息 [iphone7/iphonex]

```
{"errMsg":"getConnectedBluetoothDevices:fail no device,http://ask.dcloud.net.cn/article/282","errCode":10002}
```