Modify primary navigation Behat tests to ensure tests still pass

Modify primary navigation Behat tests to ensure tests still pass.

During the development of the primary navigation it is highly likely existing behat tests will start failing due to how tightly tied the navigation can be with our behat testing.
Before we push our frontend code to integration we need to ensure we are not introducing new failures by migrating existing behat tests to the new navigation where required.

It is possible we may need to deprecate existing behat steps or migrate them over to theme_classic's behat step overrides and implement new steps for theme_boost/Moodle core

Acceptance criteria

• Existing behat tests continue to pass across both classic & boost (no introduced failures)