Fix hardcoded listenerTag name in error message
bug #9940 [EventDispatcher] Fix hardcoded listenerTag name in error message (lemoinem)

This PR was submitted for the 2.3-dev branch but it was merged into the 2.3 branch instead (closes #9940).

Discussion
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[EventDispatcher] Fix hardcoded listenerTag name in error message

| Q             | A
| ------------- | ---
| Fixed tickets | N/A
| License       | MIT

Just as the title say, there was a kernel.event_listener string hardcoded in an error message although everywhere else in this class it is stored in the `$listenerTag` property.

Commits
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8c91537 [EventDispatcher] Fix hardcoded listenerTag name in error message