add test data to manifest

[atravitz]

specifically, we need to include:

• openfe/tests/data/openmm_rfe/benzene_toluene_hybrid_top/hybrid_topology_atoms.csv
• openfe/tests/data/openmm_septop/system.xml.bz2

Checklist

• Added a news entry

Developers certificate of origin

• I certify that this contribution is covered by the MIT License here and the Developer Certificate of Origin at https://developercertificate.org/.

[github-actions]

No API break detected ✅

[atravitz]

@mikemhenry do you have thoughts on why our package install tests didn't catch this? https://github.com/OpenFreeEnergy/openfe/actions/runs/18672070570/job/53234967237

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.88%. Comparing base (84e090b) to head (23b067f).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1603      +/-   ##
==========================================
- Coverage   95.33%   92.88%   -2.45%     
==========================================
  Files         183      183              
  Lines       15765    15765              
==========================================
- Hits        15030    14644     -386     
- Misses        735     1121     +386     

Flag	Coverage Δ
fast-tests	92.88% <ø> (?)
slow-tests	?

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[mikemhenry]

I'll look into this since this the point of these tests is to catch stuff like this!

[IAlibay]

@mikemhenry - we were discussing this a bit earlier, we think the slow tests aren't working properly, 14 mins is too short given the slow tests take hours to run.