Error on sr.probeNfsExists

[Danp2]

Describe the bug
XO generates an error during the creation of an NFS SR if you chose a path from the dropdown and then switch back to the default of "No selected value"

To Reproduce
Steps to reproduce the behavior:

1. Go to 'Created a new SR'
2. Fill in the form
3. Click the search button to fill the dropdown
4. Select one of the valid paths in the dropdown
5. Select the original "No selected value" entry from path dropdown
6. See error

Expected behavior
XO shouldn't attempt to probe the NFS server when the user picks "No selected value" from the dropdown

Log

sr.probeNfsExists
{
  "host": "dfd93f0e-08f7-4cac-8f9c-1eb698cd0c5c",
  "server": "192.168.1.65",
  "serverPath": "No selected value"
}
{
  "code": "SR_BACKEND_FAILURE_103",
  "params": [
    "",
    "The serverpath argument is not valid [opterr=serverpath is No selected value]",
    ""
  ],
  "call": {
    "method": "SR.probe",
    "params": [
      "OpaqueRef:e2781353-8cd6-0938-108d-1b7933d4c739",
      {
        "server": "192.168.1.65",
        "serverpath": "No selected value"
      },
      "nfs",
      {}
    ]
  },
  "message": "SR_BACKEND_FAILURE_103(, The serverpath argument is not valid [opterr=serverpath is No selected value], )",
  "name": "XapiError",
  "stack": "XapiError: SR_BACKEND_FAILURE_103(, The serverpath argument is not valid [opterr=serverpath is No selected value], )
    at Function.wrap (/opt/xen-orchestra/packages/xen-api/src/_XapiError.js:16:12)
    at /opt/xen-orchestra/packages/xen-api/src/transports/json-rpc.js:41:27
    at AsyncResource.runInAsyncScope (node:async_hooks:199:9)
    at cb (/opt/xen-orchestra/node_modules/bluebird/js/release/util.js:355:42)
    at tryCatcher (/opt/xen-orchestra/node_modules/bluebird/js/release/util.js:16:23)
    at Promise._settlePromiseFromHandler (/opt/xen-orchestra/node_modules/bluebird/js/release/promise.js:547:31)
    at Promise._settlePromise (/opt/xen-orchestra/node_modules/bluebird/js/release/promise.js:604:18)
    at Promise._settlePromise0 (/opt/xen-orchestra/node_modules/bluebird/js/release/promise.js:649:10)
    at Promise._settlePromises (/opt/xen-orchestra/node_modules/bluebird/js/release/promise.js:729:18)
    at _drainQueueStep (/opt/xen-orchestra/node_modules/bluebird/js/release/async.js:93:12)
    at _drainQueue (/opt/xen-orchestra/node_modules/bluebird/js/release/async.js:86:9)
    at Async._drainQueues (/opt/xen-orchestra/node_modules/bluebird/js/release/async.js:102:5)
    at Immediate.Async.drainQueues [as _onImmediate] (/opt/xen-orchestra/node_modules/bluebird/js/release/async.js:15:14)
    at processImmediate (node:internal/timers:464:21)
    at process.topLevelDomainCallback (node:domain:152:15)
    at process.callbackTrampoline (node:internal/async_hooks:128:24)"
}

Desktop (please complete the following information):

• xo-server: 5.83.0
• xo-web: 5.88.0
• hypervisor: XCP-ng 8.2.0

[julien-f]

The serverPath is incorrect, the UI should not send that.