[12.x] Fix adding setTags method on new cache flush events

[erikn69]

• Closes Broken CacheFlushing event on TaggedCache #55322
• Closes Missing flushed cache event on Illuminate\Cache\TaggableStore #55101
• Closes [12.x] Add CacheFlushed Event #55142 (comment)

Why

In #55121 (comment), Taylor said that the new CacheFlushed or CacheFlushing events should not extend CacheEvent. This makes sense since the CacheEvent is for events with a specific $key.

However, that means that we now have cache events that do not share a common ancestor and these events cannot have their tags set in TaggedCache (or RedisTaggedCache).

What

This PR attempts to fix this issue by adding a TaggedCacheEvent abstract class with a setTags method and making CacheEvent, CacheFlushing, and CacheFlushed extend it.

[taylorotwell]

I still find this confusing. I don't think CacheEvent should extend TaggedCacheEvent if we are going to re-architect things. Frankly I don't even know what we are trying to solve here. Can we ground it in reality a bit by discussing what end-user problem we are trying to solve or what you're trying to do in a package that is impossible right now in the current state of the code?

[Levivb]

At the moment I can't update past Laravel 12.3.0 because of a dispatched event on which ->setTags() is called during a clear on a Cache repository supporting tags, but that method doesn't existing on the event

CacheFlushing and CacheFlushed events are introduced in https://github.com/laravel/framework/pull/55142/files

To ground it in reality, the framework contains a bug which ideally should be solved :)

[systemsolutionweb]

Can we ground it in reality a bit by discussing what end-user problem we are trying to solve

A bug

Error: Call to undefined method Illuminate\Cache\Events\CacheFlushing::setTags()

[taylorotwell]

Can we just add setTags to those events then? I don't really like CacheEvent extending TaggedCacheEvent - that doesn't totally make sense to me from an object hierarchy point of view, even if it does basically match what is in the code now.

[taylorotwell]

Temporarily added this: 5291e19