cluster: wait for ssh connectivity before check for pull-secret

During CI failure it is observe sometime following error happen when
checking the pull secret present on the disk. This PR make sure that ssh
connectivity is present before checking pull-secret.
```
DEBU SSH command results: err: ssh: unexpected packet in response to channel open: <nil>, output:
DEBU error: Temporary error: ssh command error:
```

Author: praveenkumar

pkg/crc/cluster/cluster.go

@@ -447,6 +447,9 @@ func (p *PullSecretMemoizer) Value() (string, error) {
 func WaitForPullSecretPresentOnInstanceDisk(ctx context.Context, sshRunner *ssh.Runner) error {
 	logging.Info("Waiting until the user's pull secret is written to the instance disk...")
 	pullSecretPresentFunc := func() error {
+		if err := sshRunner.WaitForConnectivity(ctx, 30*time.Second); err != nil {
+			return err
+		}
 		stdout, stderr, err := sshRunner.RunPrivate(fmt.Sprintf("sudo cat %s", vmPullSecretPath))
 		if err != nil {
 			return fmt.Errorf("failed to read %s file: %v: %s", vmPullSecretPath, err, stderr)