Migrate `react-router-dom` from v5 to v6

[Michaeldremy]

Synk has alerted that react-router-dom needs to be upgrade. Due to migrating to a new major version more work will be required to complete this task.

• upgrade react-router-dom from 5.3.4 to 6.0.0

There is quite a lot of changes required for migrating from v5 to v6 outlined in the react-router-dom documentation.

[Michaeldremy]

Making note that Bump path-to-regexp from 1.8.0 to 1.9.0 can't be fixed until react-router-dom upgrade happens as path-to-regexp is tied to the package.

[billhimmelsbach]

We were able to update path-to-regexp without updating react-router-dom: #2440