Import SSH PrivateKey From File not work

### electerm-web Version and download file extension(electerm-web版本和下载文件后缀)

2.38.70

### Platform detail (平台详情)

web

### What steps will reproduce the bug?(重新问题的详细步骤)


consloe.log

```code
"The "path" argument must be of type string or an instance of Buffer or URL. Received null"
"TypeError [ERR_INVALID_ARG_TYPE]: The "path" argument must be of type string or an instance of Buffer or URL. Received null
at open (node:internal/fs/promises:581:10)
at Object.readFile (node:internal/fs/promises:1027:20)
at Object.readFile (file:///app/electerm-web/src/app/lib/fs.js:316:18)
at handleFs (file:///app/electerm-web/src/app/server/fs.js:9:11)
at WebSocket. (file:///app/electerm-web/src/app/server/dispatch-center.js:172:9)
at WebSocket.emit (node:events:517:28)
at Receiver.receiverOnMessage (/app/electerm-web/node_modules/ws/lib/websocket.js:1068:20)
at Receiver.emit (node:events:517:28)
at Receiver.dataMessage (/app/electerm-web/node_modules/ws/lib/receiver.js:517:14)
at /app/electerm-web/node_modules/ws/lib/receiver.js:468:23"

```

### What should have happened?(期望的结果)

should save private key, but not

### Would this happen in other terminal app(是否能够在其他同类软件重现这个问题)

_No response_

### Additional information(其他任何相关信息)

_No response_