`device-pine64-pinenote-sway.post-upgrade` should check if `sway_hrdl`
is enabled but not installed (like in the case of upgrading from v7-r0
to v8-r0) before setting default session back to `sway`. Else, every
upgrade will set the session back to sway.
Part-of: <https://gitlab.postmarketos.org/postmarketOS/pmaports/-/merge_requests/7644>