status/bluetooth: Show immediate feedback on toggle

status/bluetooth: Show immediate feedback on toggle

Since commit 6a23e8ee0f4, we use the adapter state (that includes
transitional state) to indicate progress when a state change takes
a long time.

However on many systems, the delay happens on the rfkill side,
before a change request even reaches the adapter.

Address this by temporarily overriding the adapter-state with the
expected transitional state, until an actual adapter state change
occurs.

https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/5773

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2815>