Remove restriction on xeus

[mcbarton]

Now that the PR updating xeus-cpp to be compatible with xeus 6.0 has gone in, this PR is needed to make the Emscripten ci again.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 79.56%. Comparing base (852f6d4) to head (a146a0e).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #845   +/-   ##
=======================================
  Coverage   79.56%   79.56%           
=======================================
  Files          11       11           
  Lines        4013     4013           
=======================================
  Hits         3193     3193           
  Misses        820      820           

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[mcbarton]

@Vipul-Cariappa @aaronj0 This PR fixes the issue with the Emscripten ci on main, but something has happened to make jobs fail when running cppyy tests. I'll leave that issue for you 2 to sort out.

[mcbarton]

The cppyy test failures are also happening for cppyys ci on main https://github.com/compiler-research/cppyy/actions/runs/22874491199

[aaronj0]

The cppyy test failures are also happening for cppyys ci on main https://github.com/compiler-research/cppyy/actions/runs/22874491199

Hi, the failures have been fixed so you can rerun and merge this PR once the checks are clear

edit: I have triggered a rerun

[mcbarton]

The cppyy test failures are also happening for cppyys ci on main https://github.com/compiler-research/cppyy/actions/runs/22874491199

Hi, the failures have been fixed so you can rerun and merge this PR once the checks are clear

edit: I have triggered a rerun

@aaronj0 I will be very busy today, so may not notice when it passes. Please merge for me if you see it has passed.