docs: fix invalid command line in the README of transfer-00-prerequisites

[iwasakims]

What this PR changes/adds

fix the invalid command line of README of transfer-00-prerequisites.

Why it does that

extra | before -s causes error on copying from browser and pasting.

$ curl -H 'Content-Type: application/json' \
     -d @transfer/transfer-00-prerequisites/resources/dataplane/register-data-plane-provider.json \
     -X POST "http://localhost:19193/management/v2/dataplanes" | -s | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
curl: (7) Failed to connect to localhost port 19193 after 0 ms: Connection refused
-s: command not found

Linked Issue(s)

Closes #148

[github-actions]

'We are always happy to welcome new contributors ❤️ To make things easier for everyone, please - make sure to follow our contribution guidelines, - check if you have already signed the ECA, and - relate this pull request to an existing issue or discussion.'

[ndr-brt]

thanks