Activity note connector displayed incorrectly in dark mode when work item open in modal

Summary

Line connecting notes only shows after the last note.

Steps to reproduce

Open a task from an issue (so it opens in a modal).

Example Project

gitlab

What is the current bug behavior?

Connector line shows after the last item only and is black.

Behavior appears correct outside of dark mode.

What is the expected correct behavior?

Connector line is present between first and last item, and not after last item. Line is gray.

Relevant logs and/or screenshots

Work item (task)	Issue

Output of checks

Results of GitLab environment info

Expand for output related to GitLab environment info

(For installations with omnibus-gitlab package run and paste the output of: \\\\\\\`sudo gitlab-rake gitlab:env:info\\\\\\\`) (For installations from source run and paste the output of: \\\\\\\`sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production\\\\\\\`)

Results of GitLab application Check

Expand for output related to the GitLab application check

(For installations with omnibus-gitlab package run and paste the output of: \\\`sudo gitlab-rake gitlab:check SANITIZE=true\\\`) (For installations from source run and paste the output of: \\\`sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true\\\`) (we will only investigate if the tests are passing)

Possible fixes