[MRG] fix loading without age information / single-column .tsv

[skjerns]

PR Description

When loading participants.tsv with only a single column (only participant ids), p_age is empty, and can therefore not be created. See also #891 . This simple fix resolves this problem.

Merge checklist

Maintainer, please confirm the following before merging:

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

[welcome]

Hello! 👋 Thanks for opening your first pull request here! ❤️ We will try to get back to you soon. 🚴🏽‍♂️

[sappelhoff]

Thanks for the fix @skjerns - would you mind adding a small test here? --> https://github.com/mne-tools/mne-bids/blob/main/mne_bids/tests/test_report.py

also: it's just a small fix, but could you add an entry to the changelog? https://github.com/mne-tools/mne-bids/blob/main/doc/whats_new.rst

It'll also showcase your first PR contribution to mne-bids :-)

[codecov]

Codecov Report

Merging #912 (c69ee50) into main (8a29504) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #912   +/-   ##
=======================================
  Coverage   94.78%   94.78%           
=======================================
  Files          23       23           
  Lines        3488     3488           
=======================================
  Hits         3306     3306           
  Misses        182      182           

Impacted Files	Coverage Δ
mne_bids/report.py	91.32% <100.00%> (ø)

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[sappelhoff]

something seems to have gone wrong with rebasing and/or merging main into this PR 🤔 There are lots of changes that shouldn't be changes

[skjerns]

something seems to have gone wrong with rebasing and/or merging main into this PR 🤔 There are lots of changes that shouldn't be changes

damn, I might have pulled from the wrong main. I'll tried to fix it - is it fine now?

[sappelhoff]

looks much better now!

alignment with main was fixed

[hoechenberger]

Whoops, CI failing now, can you have a look? If you're busy, I might be able to take over tomorrow

[welcome]

🎉 Congrats on merging your first pull request! 🥳 Looking forward to seeing more from you in the future! 💪

[agramfort]

thx @skjerns