pip prod(deps): update scipy requirement from <1.15.4 to <1.16.4

Updates the requirements on [scipy](https://github.com/scipy/scipy) to permit the latest version.
- [Release notes](https://github.com/scipy/scipy/releases)
- [Commits](scipy/scipy@v0.1.0...v1.16.3)

---
updated-dependencies:
- dependency-name: scipy
  dependency-version: 1.16.3
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements-optional.txt

@@ -1,7 +1,7 @@
 matplotlib<3.10.9
 pillow>11,<12.0.1
 pyrevolve==2.2.7
-scipy<1.15.4
+scipy<1.16.4
 distributed<2025.11.1
 click<9.0
 cloudpickle<3.1.3

requirements-testing.txt

@@ -3,7 +3,7 @@ pytest-runner<6.0.2
 pytest-cov<7.0.1
 flake8-pyproject>=1.2.3,<1.2.5
 nbval<0.11.1
-scipy<1.15.4
+scipy<1.16.4
 pooch<1.8.3
 click<9.0
 cloudpickle<3.1.3