[lldb][NFC] Don't inherit from UserID in ValueObject

ValueObject inherits from UserID which is just a bad idea:

* The inheritance gives ValueObject some member functions that are at best
  misleading (such as `Clear()` which doesn't clear any value beside `id`).

* It allows passing ValueObject to the overloaded operators for UserID (such as
  `==` or `<<` which won't actually compare or print anything in the ValueObject).

* It exposes the `SetID` and `Clear` which both allow users to change the
  internal id value.

Similar to D91699 which did the same for Process

Reviewed By: #lldb, JDevlieghere

Differential Revision: https://reviews.llvm.org/D97205