For example, with the pageLoaded event. Probably with others.
Guard the token deduplication logic with the token existence.
Reported originally here T167273#3364463 :
- Events with null or undefined link interaction tokens aren't deduplicated.
- It may be useful to have a whitelist for events that can have null or undefined link interaction tokens associated with them e.g. disabled
- This should be done in [the eventLogging change listener](https://github.com/wikimedia/mediawiki-extensions-Popups/blob/38970b488d2c02a9ef2c3f7e9d7e2adb7601f2c3/src/changeListeners/eventLogging.js#L71-L77).