fix save modal params plugin

[pavluk]

Is your request related to issue Indicate the issue with which your request is associated [e.g. Pull Request for Issue # .]

Summary of changes A clear and concise description of what you have changed.

Testing Instructions Steps for testing:

1. Apply patch
2. Go to '...'
3. Click on '....'
4. Scroll down to '....'
5. See result

Expected result A clear and concise description of what you expected to happen.

Actual result A clear and concise description of what should change.

Screenshots If applicable, add screenshots to explain the changes.

System Information (please complete the following information):

• Extensions version [e.g. 1.0.0]
• PHP version: [e.g. 7.2]
• Server OS: [e.g. Linux/Windows]

• Browser [e.g. firefox, chrome, safari, ie]

  Additional context Add any other context about the problem here.