snap connections doesn't work as expected when interface attributes change

[Jamie Strandboge]

In looking at https://forum.snapcraft.io/t/allow-optical-drive-write-support-for-makemkv/13807/2, I issued the following snap declaration for makemkv:

plugs:
  hardware-observe:
    allow-auto-connection: true
  optical-drive:
    allow-connection: true
    deny-auto-connection:
      plug-attributes:
        write: true

I then install makemkv from 'stable':

$ sudo snap install makemkv
makemkv 1.14.5 from Daniel Llewellyn (diddledan) installed

which has the following snap.yaml:
apps:
  makemkv:
  plugs:
  - optical-drive

$ snap connections makemkv|grep optical
optical-drive makemkv:optical-drive :optical-drive -

So far so good. Now, if I 'snap refresh makemkv --edge' I see something weird with snap connections:

$ sudo snap refresh makemkv --edge
makemkv (edge) 1.14.5 from Daniel Llewellyn (diddledan) refreshed

which has the following snap.yaml:

plugs:
  optical-write:
    interface: optical-drive
    write: true
apps:
  makemkv:
    plugs:
    - optical-write

$ snap connections makemkv|grep optical
optical-drive makemkv:optical-drive :optical-drive -
optical-drive makemkv:optical-write - -

So, 'optical-drive' is shown as connected when it isn't even plugged, and optical-write is disconnected (as it should be).

But, the interface is not actually connected:
$ grep optical /var/lib/snapd/apparmor/profiles/snap.makemkv.*
$

This is likely related to bug 1848516 but filing separately since it is a different variation (ie, the interface isn't 'dropped' from the snap.yaml per se since optical-write is there).