Description

I've noticed quite a few random failures in CI lately of one of the cases in test_activation, where the reaction rate is estimated by tallying a 100-group flux and then collapsing it with cross sections. It is expected that you don't get the exactly right answer because it doesn't account for energy self-shielding within the groups, which is why the test is occasionally failing. This PR bumps up the tolerance for that case which should mitigate the random failures.

Checklist

• I have performed a self-review of my own code
• I have run clang-format (version 15) on any C++ source files (if applicable)
• I have followed the style guidelines for Python source files (if applicable)
• I have made corresponding changes to the documentation (if applicable)
• I have added tests that prove my fix is effective or that my feature works (if applicable)