update Coach routing behavior

[thanksameeelian]

Observed behavior

when a user is a multi-facility admin & selects a Coach subtopic from sidenav, they will be redirected to an "All Facilities" page with links leading to each facility's "Class home" page (or "All classes" page if facility has multiple classes, the links on which resolve to "Class home" for each class), rather than the subtopic the user initially selected.

Proposed behavior

mirror the routing updates introduced in #10550:

• if a multi-facility user selects Coach subtopic, they should be redirected to an "All Facilities" page populated with links to each facility's page for that subtopic (e.g. if a multi-facility user has a facility with multiple classes, clicking on Plan in the sidenav will lead you to "All Facilities", and clicking on the facility will lead to the "All classes" page, where the links for each class resolve directly to that class's Plan when selected - in facility tab navigation bug #10550 similar routing is done with subtopic names passed as route params that are taken in as props by the "All facilities" route)
• adjust backlink to retain information about the subtopic being navigated away from & use that prop to construct subtopic-specific links on "All Facilities"/"All Classes" page (PR addressing Missing 'All classes' link on device with multiple facilities #10673 will add back links when needed into all main Coach subtopic pages, but will not introduce passing subtopic-specific information during navigation)

User-facing consequences

Users must select a subtopic in order to navigate to Coach plugin but, in the case of a multi-facility user, once they select a link on the "All Facilities" page, they will always end up getting directed to "Class home" regardless of their initial selection