Improve empty state for Todos

Proposal

We should improve the empty state for ToDos. Specifically, the second line text is not super useful and has links that don't have meaningful information. Could this second line simply be removed?

Implementation guide

The empty state copy is in the following files:

• Main heading variations: https://gitlab.com/gitlab-org/gitlab/-/blob/master/app/helpers/todos_helper.rb#L175-L179
• Secondary text and links: https://gitlab.com/gitlab-org/gitlab/-/blob/master/app/views/dashboard/todos/index.html.haml#L107

Proposed text for the empty state:

No open to-dos

Not sure where to go next? Take a look at your assigned issues or merge requests.

What actions create to-do items?