Fix flaky test spec/features/projects/work_items/work_item_spec.rb:42

What does this MR do and why?

Related to #415331 (closed)

Because there is more than one comment in the work item, the following line might return the incorrect note if the target comment hasn't been submitted:

page.within('.timeline-entry.note.note-wrapper.note-comment:last-child') do

The menu for the note actions won't include the delete option if the comment was authored by a different user, we need to make sure we are clicking on the comment added by the current user:

❯ rspec './spec/features/projects/work_items/work_item_spec.rb[1:1:7:3:1]' --seed 57724

Randomized with seed 57724
Test environment set up in 5.60768 seconds
Starting the Capybara driver server...
2023-06-14 12:50:30 WARN Selenium [:logger_info] Details on how to use and modify Selenium logger:
  https://selenium.dev/documentation/webdriver/troubleshooting/logging#ruby

2023-06-14 12:50:30 WARN Selenium applicable driver not found; attempting to install with Selenium Manager
Capybara starting Puma...
* Version 6.3.0 , codename: Mugi No Toki Itaru
* Min threads: 0, max threads: 4
* Listening on unix:///var/folders/w2/gvt6bfks463ftmksytjppj0m0000gn/T/20230614-51252-2lgp5k

Finished in 28.7 seconds (files took 12.48 seconds to load)
1 example, 0 failures

Randomized with seed 57724

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