Remove unused generic from RedisKeyExpiredEvent #2106

[gisu1102]

Closes #2106

Motivation

RedisKeyExpiredEvent<T> declares a generic type parameter that is not used anywhere in the current API.
The presence of <T> suggests type safety that the event does not actually provide, which can be confusing for users.

Changes

• Removed the unused generic type parameter from RedisKeyExpiredEvent
• Kept the existing runtime behavior unchanged (getValue() continues to return Object)

Rationale

The original issue outlines two possible directions.
This PR intentionally takes the minimal approach by removing the unused generic parameter.

Implementing a typed getValue(): T would require additional design decisions around
value deserialization and type resolution, which felt out of scope for a small cleanup.
Removing the unused generic improves API clarity without introducing new semantics.

Compatibility

This is a source-level incompatible change for code explicitly using RedisKeyExpiredEvent<T>.
However, since the generic parameter was unused and did not provide actual type safety,
the migration impact is minimal and runtime behavior remains unchanged.

Tests

• Existing unit tests pass

[mp911de]

That's an API change that we need to wait with, otherwise, existing application code will fail to compile.

[gisu1102]

Thanks for the clarification.
Understood — this is an API-breaking change and should be deferred to the next major release. Happy to revisit when work on the next major version starts.