Remove Products Set Menu entry.

[budzanowski]

Changes proposed in this Pull Request:

The Products Sets menu entry is redundant. The Product sets tab from the Marketing -> Facebook is enough to access the feature.

The entry has been removed. The file filter has been update to highlight the proper menu item.

• [ ] Do the changed files pass phpcs checks? Please remove phpcs:ignore comments in changed files and fix any issues, or delete if not practical.

Screenshots:

Detailed test instructions:

1. Marketing, Product Sets menu item should not be present
2. Access via Marketing -> Facebook -> Product Sets tab should work.
3. Products Sets functionality should not be broken.

Additional details:

none

Changelog entry

Update: Remove Marketing Products Sets menu entry.