Fix Remaining Console Warnings #50

Describe the bug
We're still getting a couple of warnings, thanks @NguyenDa18 for letting us know.

To Reproduce
Steps to reproduce the behavior:

1. Go to the developer console, there's a couple of warnings there

Expected behavior
No warnings should appear

Additional context
We have the following tasks to do:

• making a 404 page
• validateDOMNesting(...): cannot appear as a descendant of .
• Warning: Each child in a list should have a unique "key" prop.
• Check the render method of DonationCard