fix compare_motif_list location call in motif data frame

[ssenan]

• Resolves compare_motif_list function outputs error when used in isolation #204
• Changes dtype of first column to object in functions df_motifs_a and df_motifs_b in test_metrics.py
• Same change in compare_motif_list in metrics.py

[ssenan]

@Mergifyio queue default

[mergify]

queue default

🟠 Waiting for conditions to match

Details

• any of: [:twisted_rightwards_arrows: queue conditions]
  • all of: [:pushpin: queue conditions of queue default]
    • #approved-reviews-by>=1 [🛡 GitHub branch protection]
    • #changes-requested-reviews-by=0 [🛡 GitHub branch protection]
• -draft [:pushpin: queue requirement]
• -mergify-configuration-changed [:pushpin: queue -> allow_merging_configuration_change setting requirement]

[codecov]

Codecov Report

Merging #205 (4c49f0b) into main (5c9463c) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #205   +/-   ##
=======================================
  Coverage   24.50%   24.50%           
=======================================
  Files          16       16           
  Lines         910      910           
  Branches      103      103           
=======================================
  Hits          223      223           
  Misses        684      684           
  Partials        3        3           

Files Changed	Coverage Δ
src/dnadiffusion/metrics/metrics.py	39.47% <100.00%> (ø)
tests/test_metrics.py	100.00% <100.00%> (ø)