Update Statistics requirement to 1.11.1 in /test

Updates the requirements on [Statistics](https://github.com/JuliaStats/Statistics.jl) to permit the latest version.
- [Release notes](https://github.com/JuliaStats/Statistics.jl/releases)
- [Commits](JuliaStats/Statistics.jl@v1.4.0...v1.11.1)

---
updated-dependencies:
- dependency-name: Statistics
  dependency-version: 1.11.1
  dependency-type: direct:production
...

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Author: dependabot[bot]

test/Project.toml

@@ -19,5 +19,6 @@ DecisionFocusedLearningAlgorithms = "0.2.3"
 DecisionFocusedLearningBenchmarks = "0.6.1"
 Documenter = "1"
 MLUtils = "0.4"
+Statistics = "1.11.1"
 Test = "1"
 ValueHistories = "0.5"