propagate is_dir to nested-pandas read_parquet

[dougbrn]

Closes #578

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.49%. Comparing base (e34ae82) to head (13a126a).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #626   +/-   ##
=======================================
  Coverage   93.49%   93.49%           
=======================================
  Files          50       50           
  Lines        2444     2444           
=======================================
  Hits         2285     2285           
  Misses        159      159           

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[github-actions]

Before [e34ae82]	After [93bf07a]	Ratio	Benchmark (Parameter)
1.05±0.04ms	1.06±0.02ms	1.01	benchmarks.time_test_cone_filter_multiple_order
13.1±0.7ms	13.1±0.3ms	1	benchmarks.Suite.time_inner_pixel_alignment
403±1ms	401±0.8ms	1	benchmarks.Suite.time_outer_pixel_alignment
272±2ms	272±3ms	1	benchmarks.time_open_large_catalog
271±1ms	272±1ms	1	benchmarks.time_small_cone_large_catalog
122±0.4ms	121±0.6ms	1	benchmarks.time_test_alignment_even_sky
42.3±0.7ms	41.9±0.6ms	0.99	benchmarks.Suite.time_pixel_tree_creation
44.2±0.1ms	43.8±0.1ms	0.99	benchmarks.time_open_midsize_catalog

Click here to view all benchmarks.