Dynamic Matrix and Dynamic Panel - Allow users to select unique values by removing already selected choices from a list of available options

[JaneSjs]

In a Dynamic Matrix, a column may have the isUnique option enabled. Thus, if a user selects a duplicate value within a column, a validation error appears:

However, a dynamic panel doesn't have such an option.
Besides, users request that we hide / disable choices which were already selected in other dynamic rows or panels.

• T21572 - Dropdown in Dynamic Panel - don't show choice previously selected
  https://surveyjs.answerdesk.io/internal/ticket/details/T21572
  in many cases there is a need to prevent user from selecting duplicate choice at all

• T21572 - Dropdown in Dynamic Panel - don't show choice previously selected
  https://surveyjs.answerdesk.io/internal/ticket/details/T21572

Consider introducing an option which would allow developers to hide duplicate values in dropdowns within dynamic panels and matrices.