tag acceptance test features/scenarios that require the files_sharing_app

[phil-davis]

We want to be able to run acceptance tests against a system that has the files_sharing app disabled.

Tag the features/scenarios that require the files_sharing app, so we can easily include or exclude them.

files_sharing-app-required

See PR #32864 (comment)

[ownclouders]

GitMate.io thinks possibly related issues are #22492 (test), #22485 (test), #31579 (test), #31516 (Acceptance test coding standard changes), and #32351 (Standardize acceptance test skip tags).