Fix json field name for notification mechanisms data

[revathyrams]

Description

The json field names were interchanged with the struct field names in my previous PR. This commit fixes it.

Types of changes

What sort of change does your code introduce/modify?

• [✅] Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [ ✅ ] My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• [✅ ] All new and existing tests passed.