client_app - each child in a list should have a unique key prop (for all the lists)

Describe the bug When I run the client_app and navigate to the Dashboard(with shifts added), Current selection page, Upcoming shifts, Previous shifts, or Shift confirmation page, I see a warning in the console stating "Each child in a list should have a unique key prop".

In continuation to the issue #65
Depends on the issue #22

To Reproduce Steps to reproduce the behavior:

Run the application and sign in with developer@slu.edu and any password
In your web browser, open "Developer tools"
In Developer tools, open the "console" tab
Navigate to a page where a list or table is displayed (Dashboard(with shifts added), Current selection page, Upcoming shifts, Previous shifts, or Shift confirmation page).
You should see "Each child in a list should have a unique key prop" warning logged to the console. See screenshot below

Expected behavior The console warning should not be displayed

Additional context A unique key has to be added to each element in the list.

oss-slu / shelter_volunteers

client_app - each child in a list should have a unique key prop (for all the lists) #70