[EventDispatcher] Improve method resolving when it is omitted in tag

[nikophil]

Q	A
Branch?	6.4
Bug fix?	no
New feature?	yes
Deprecations?	no
License	MIT
Doc PR	will be done if bugfix gets accepted

(this PR is a split of #50775)

this PR proposes to improve the listener's method resolution by:

1. checking if a method with the "camelized" name exist.
2. If it does not, we evaluate if one unique public method exists which would take the event as unique parameter (ie: the listener definition above would resolve someMethod() as the listener's method).
3. if an __invoke method exist we'll use this one without checking its parameters (this is also useful for BC)
4. Otherwise, method name needs to be provided and an exception is thrown

ping @GromNaN

(CI failures seems unrelated to this PR 🤔 )