[BUG] part of marshal step in source is removed when data-format attribute is specified

[igarashitm]

Describe the bug
From what I can see from this document the following YAML should be valid

- from:
    uri: timer:null
    steps:
    - marshal:
        data-format:
            json:
                library: Gson

but is wiped out.

it ends up with:

- from:
    uri: timer:null
    steps:
    - marshal:
        data-format:
          json: ''

To Reproduce
Steps to reproduce the behavior:

1. Open source code editor and paste above code
2. Click sync your code

Expected behavior
marshal step is preserved

Logs
If applicable, add logs to help explain your problem.

Environment (please complete the following information):

• OS: [e.g. "Linux 5.10.0-9-amd64 Using sonarcloud action to add details on PR #1 SMP Debian 5.10.70-1 (2021-09-30) x86_64 GNU/Linux"]
• Output of the mvn -version` command
• Kaoto Version [e.g. 1.0]

Additional context
Add any other context about the problem here.