Resolve all "TODO:" in the codebase

[pawelru]

Follow-up on: #1253

Resolve all "TODO:"

• inline comments: https://github.com/search?q=repo%3Ainsightsengineering%2Fteal+todo+path%3A%2F%5ER%5C%2F%2F&type=code
• test skips: https://github.com/search?q=repo%3Ainsightsengineering%2Fteal%20skip(%22todo%22)&type=code

Apparently, all of them has been introduced in the aforementioned PR

[donyunardi]

As discussed, we can remove the todo's comment under the R folder as pointed in the inline comments.

Acceptance Criteria

• Add unit test which was previously marked as to do.
• If module has duplicate labels, we need to make sure that the datasets are still being passed correctly.
• When we reload the data, the filters are remain the same from previous activities.
• teal doesn't fail when there's no datasets.