findValues sometimes returns duplicate values in Scala 3

[jadenPete]

Enumeratum version: 1.9.0
Scala version: 3.6.3

In Scala 3, if the values of an enum mix in a shared trait that extends the entry type, findValues can return duplicate values.

Here's an example on Scastie:
https://scastie.scala-lang.org/fTa1qOmAQduIGTAS9XWGmg

Observe that when the program is run, Vector(Dog, Human, Dog, Human) is printed. I'll also paste the program below:

import enumeratum.values.{StringEnum, StringEnumEntry}

sealed abstract class Animal(override val value: String) extends StringEnumEntry

object Animal extends StringEnum[Animal] {
  case object Dog extends Animal("dog") with Mammal
  case object Human extends Animal("human") with Mammal

  override lazy val values: IndexedSeq[Animal] = findValues
}

sealed trait Mammal extends Animal

println(Animal.values)

[lloydmeta]

Whoa ... that's not great. Thanks for reporting this.

Please feel free to take a stab at addressing this.

[reibitto]

Yeah, I actually just ran into this too. In our case I was able to work around it with self-types for the time being, but that's not a real solution.

[jadenPete]

Done! #436