False UnusedVariable warning for method parameters only used in overridden implementations

Consider the following example:

```java
public class App {
private static class Base {
protected void doStuff(String usedInDescendants) {}
}

private static class Descendant extends Base {
@Override
protected void doStuff(String actuallyUsed) {
System.out.println(actuallyUsed);
}
}

public static void main(String[] args) {
Base b = new Descendant();

b.doStuff("some string");
}
}
```
**Expected result**: no warnings

**Actual result**: ErrorProne complains about `usedInDescendants` parameter of `App.Base.doStuff` being unused. However, this parameter is used by the overridden method in `Descendant` class and cannot be easily removed.

There are several workarounds, but they aren't universally applicable:
* Increase the visibility of the base class - gives the type unnecessary exposure
* Make the method abstract - then the base class cannot provide a default implementation.

Even converting the `Base` to an interface with default method still triggers the warning.

A full reproducer can be found at
https://github.com/mlopatkin/errorprone-issue-reproducers/tree/trunk/unused-variable-overloaded-method

Tested with ErrorProne 2.27.1, 2.24.1 on Java 11 and Java 21.