fix play/libs/Files.java. prepare Scala 3

[xuwei-k]

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Helpful things

Fixes

fix compile error in Scala 3.

Purpose

use TemporaryFileCreator type instead of SingletonTemporaryFileCreator$

Background Context

A.scala

package example

trait A

object B extends A

C.java

package example;

public class C {
  example.B$ b = example.B$.MODULE$;
}

compile with Scala 3.1.2

[error] 4 |  example.B$ b = example.B$.MODULE$;
[error]   |  ^^^^^^^^^^
[error]   |  type B is not a member of example - did you mean example.B.type?
[error] one error found
[error] (Compile / compileIncremental) Compilation failed

References

• Scala 3 #11260