:bug: in `plot_timeseries()` with multiple models

[kellijohnson-NOAA]

@okenk noticed jagged uncertainty intervals when plotting two FIMS models that we slightly investigated.

@k-doering-NOAA originally posted this issue on FIMS. That I have since closed because I am transferring it here but it would not let me do a transfer across organizations ☹️.

Thanks to Kiva for pointing out that the uncertainty on the last plot in the FIMS intro vignette (in this section: https://noaa-fims.github.io/FIMS/articles/fims-demo.html#length) looks a little funny - the uncertainty appears "jagged". Maybe the code generating the plot needs a fix?

I believe the problem is in the plotting of the uncertainty where the groups are created for the lines but not for the uncertainty intervals. This could be completely off base though because I did not dig too deep. Happy to help if help if wanted.

[Schiano-NOAA]

Thanks for identifying this issue Kelli! I will take a look at it. I recently made a change to an issue with grouping in the area geom, but probably need something similar for line

[Schiano-NOAA]

We will be working on this bug tomorrow during our office hours!

[Schiano-NOAA]

@kellijohnson-NOAA the issue should be fixed on the branch hotfix-issue-188! We plan to merge it in soon, but could you test for the FIMS model comparison?

[kellijohnson-NOAA]

Much better 😍