Bundle products do not allow configurable products to be added

[arne-s]

Describe the bug
It is in the latest version not possible to add configurable products to a configurable products.
I am not sure if this is a bug or intentional, but in my current shop nearly all products are configurable products, so not being able to add configurable products would make the bundle option unusable.

To Reproduce
Steps to reproduce the behavior:

• Create new bundle product
• Click on "Add product" in the "Group Products" section
• The configurable products are not listed whatever the search query

Expected behavior
The configurable products should be able to be added

Additional context
I'm using version 2.1.1 but the issue is also present in the current Bagisto Demo

[jitendra-webkul]

Please note that only simple products are eligible for addition to the configuration, bundle, and grouped product types.

[Dunicotech]

Is this a feature which is going to be add in the future?