Remove unnecessary warnings from Designer layouts

Steps to Reproduce:

• In nos-test, create a new document type.
• Navigate to Designer and instantiate each of the layouts for the document type by:
  • selecting the layout from the Layout menu on the left
  • clicking on the blue Configure button
  • clicking Save
    => Error message appears:

    Warnings
    Since LTS 2017 HF05, code generation has changed for suggestion elements. Your code will keep working, but we recommend replacing these elements using drag and drop to benefit from the latest updates if you are using HF05 or newer.
    

This warning appears on every layout that is instantiated, edited or saved.

Expected behavior:

• Title should always be Warning, not Warnings.
• The warning should explicitly state what the problem is and how to fix it (it is not clear which behavior should trigger this type of warning).
• The warning should not appear when layouts are generated automatically or by using drag and drop. (If I understood the warning correctly).