`Time in draft` for pull requests metrics is always `None`

[Aloshadance]

Describe the bug

When I run the github action with the DRAFT_PR_TRACKING set to true for the pull requests metrics, I get the value None in the Time in draft column for all pull requests.
In the first screenshot, I displayed that the pull request is in draft status, but Time in draft is still None. However, the situation is the same if the pull request has already entered the Ready for Review state, having previously been in draft status.

To Reproduce

Run issue metrics in a github workflow step with DRAFT_PR_TRACKING set to true.

Expected behavior

I would like to get the correct and at least working Time in draft for pull requests.
It seems to me that the None value is valid only for those pull requests that were not in the draft status at all.

Screenshots

Additional context

runs-on: ubuntu-latest
version of issue metrics package: latest (3.23.0)

[zkoppert]

Yikes! Thanks for submitting this one. We will take a look at it and ensure there is some more test coverage in this area.

Thinking out loud: we should be tracking time spent in draft when a pull request is initially opened as draft and when it is initially opened as ready but goes back into draft.