Shell.executeSsh error handling doesn't handle multiple connection failures

[awharn]

Describe the bug

If a hostname is resolveable by multiple IP addresses, Shell will attempt to go through each one. If it fails to resolve any of the addresses, and there is more then one address that was tried, it will return with a list of errors (via AggregateError), not a single error.

Our error handling assumes that a single error was thrown. However, in this case, err.message is undefined because err is an AggregateError which contains a list of errors, not a single error. We then throw an unexpected error, and since err.message is undefined on AggregateError, no useful output is given to the user.

Error handling should be updated to check if there is an errors list on err and, if so, concatenate and display the error messages together.

[github-actions]

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[awharn]

From system tests, using localhost as an example:

AggregateError: 
        at internalConnectMultiple (node:net:1117:18)
        at afterConnectMultiple (node:net:1684:7) {
      code: 'ECONNREFUSED',
      level: 'client-socket',
      [errors]: [
        Error: connect ECONNREFUSED 127.0.0.1:22
            at createConnectionError (node:net:1647:14)
            at afterConnectMultiple (node:net:1677:16) {
          errno: -61,
          code: 'ECONNREFUSED',
          syscall: 'connect',
          address: '127.0.0.1',
          port: 22
        },
        Error: connect ECONNREFUSED ::1:22
            at createConnectionError (node:net:1647:14)
            at afterConnectMultiple (node:net:1677:16) {
          errno: -61,
          code: 'ECONNREFUSED',
          syscall: 'connect',
          address: '::1',
          port: 22
        },
        Error: connect ETIMEDOUT 127.0.0.2:22
            at createConnectionError (node:net:1647:14)
            at afterConnectMultiple (node:net:1677:16) {
          errno: -60,
          code: 'ETIMEDOUT',
          syscall: 'connect',
          address: '127.0.0.2',
          port: 22
        }
      ]
    }

This is an AggregateError that can be returned if multiple IP addresses resolve to the same hostname, and the hostname was used to initiate the connection. This is in no way shown to the user, and was coerced with some console.dir(err) statements in error handling (for demonstration/debugging purposes).