MRG: Fix bug with writing ctc/cal for emptyroom

[larsoner]

PR Description

Closes #1188

Merge checklist

Maintainer, please confirm the following before merging. If applicable:

• [ ] All comments are resolved
• [ ] This is not your own PR
• [ ] All CIs are happy
• [ ] PR title starts with [MRG]
• [ ] whats_new.rst is updated
• [ ] New contributors have been added to CITATION.cff
• [ ] PR description includes phrase "closes <#issue-number>"

[codecov[bot]]

Codecov Report

Merging #1189 (f6894b0) into main (b96c489) will increase coverage by 0.02%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1189      +/-   ##
==========================================
+ Coverage   97.62%   97.64%   +0.02%     
==========================================
  Files          40       40              
  Lines        8664     8671       +7     
==========================================
+ Hits         8458     8467       +9     
+ Misses        206      204       -2     

Files	Coverage Δ
mne_bids/path.py	97.27% <100.00%> (+<0.01%)	:arrow_up:
mne_bids/tests/test_write.py	99.50% <100.00%> (+<0.01%)	:arrow_up:
mne_bids/utils.py	95.93% <100.00%> (+1.01%)	:arrow_up:

[hoechenberger]

Thanks @larsoner!