Do not restore adobeconnect activities if no userdata selected and do not delete a meeting off the adobeconect server if multiple activities point to it

Environment
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Moodle 1.9.17+
Adobeconnect block version 2012020200
Adobe Connect Pro 8 (privately hosted)

Description of the issue(s)
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1. When restoring a course with adobeconnect activities 'with userdata' or 'without userdata', the restored activity always points to the same meeting on the AC server as the previous one (shared SCOID), meaning there are multiple activities in Moodle pointing to the same meeting room after a backup/restore (as part of a standard course rollover) or an 'import' into another course site is performed. Because all the activities point to the same activity, recordings for the original meeting show up in all the Moodle activities and are accessible to participants in any of those courses. Also, if both courses are actively being used, the participants & hosts from the two courses might schedule a session at the same time and 'meet' in the room unintentionally.

2. If you have multiple activities pointing to the same AC meeting, and you delete one of the activities, it immediately deletes the meeting from the AC server, making all other activities that point to that meeting orphan activities. This can result in the unintended deletion of recordings off the AC server

Example Scenario illustrating the issue(s)
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You have an established course with an AC activity with recordings. You create a new course which you want to base off the first one. You import its course content (which does not bring cross user data) into the new site. You enter the AC activity in the new course and realise that it has recordings attached to it - which you do not want in the new course. You delete the AC activity from the new course. Then you enter into the original course and wonder why the original AC activity displays "No meeting found on server" and you can no longer access your meeting room / recordings.

Expected Behaviour
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1. When restoring a course with adobeconnect activities 'with userdata', the restored activity should continue to point to the same meeting (and display its recordings). When restoring a course with adobeconnect activities 'without userdata' the adobeconnect activity should not be restored at all.

2. If there are multiple Moodle activities pointing to the same AC meeting, and you delete one of the activities, it should only delete the meeting from the AC server if there are no other Moodle activities pointing to the same meeting.

Workarounds
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Hide Adobe Connect activities (do not delete them) if you have imported data from a course with AC activities or created a new course from the backup of an old course having selected not to bring user data across.

Resolution
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1. Add a check to adobeconnect_restore_mods() for whether userdata is to be included or not, and only restore activity if user data is included.
2. Add a check to adobeconnect_delete_instance() for other activities pointing to the same meeting on the Adobe Connect server (identified by SCOID) and only delete it from the server if no other activities point to the meeting.

Patch and github repo
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Links to be provided in comments section once I get a tracker number for this issue