Inconsistent trailing slashes in routes

[alyssadai]

In the PR for:

• Routes without trailing slash cause 307 redirect which breaks reverse proxies via paths #327

we globally disabled redirection of trailing slashes, such that routes by default will now only work if they are accessed exactly as defined (e.g., if the /query route is defined without a trailing slash, then /query/ will not work).

As part of the issue spec, we decided that we would globally define routes without the trailing slash for convenience and URLs, e.g.:

api.neurobagel.org/query -> response
api.neurobagel.org/query/ -> no response
api.neurobagel.org/attributes/nb:Assessment -> response
api.neurobagel.org/attributes/nb:Assessment/ -> no response

However, when we then refactored the generic /attributes route into variable-specific routes in:

• [REF] Split generic /attributes endpoints into attribute-specific routers #358

we accidentally reintroduced the trailing slash into the variable routers. The result is that at the moment, we are not consistent with where we expect trailing slashes:

api.neurobagel.org/query -> works
api.neurobagel.org/query/ -> doesn't work
api.neurobagel.org/assessments -> doesn't work
api.neurobagel.org/assessments/ -> works

Steps to implement

• standardize the router definitions so that we do not expect / for the base of each route
• test whether the root of app is reachable when path prefix has or lacks a trailing slash
• check that custom favicon still works
• ensure that behaviour is predictable with generic stripped path prefix NGINX config (note default merge_slashes behaviour)

NOTE: The query tool and f-API may also be affected by this change