Fix CI for Numpy 2.4

[nilsvu]

Proposed changes

CI has been failing since the release of Numpy 2.4.

Fixes #6527.

Upgrade instructions

Code review checklist

• The code is documented and the documentation renders correctly. Run
  make doc to generate the documentation locally into BUILD_DIR/docs/html.
  Then open index.html.
• The code follows the stylistic and code quality guidelines listed in the
  code review guide.
• The PR lists upgrade instructions and is labeled bugfix or
  new feature if appropriate.

Further comments

[wthrowe]

It's still failing, but now because of #6527.

[nilsvu]

Pushed a fix for #6527.

[nilsvu]

Merging to fix CI