Fix read_parquet bug for extended dtypes from remote storage

[rjzamora]

This fixes a read_parquet bug discovered while iterating on #9589

Without this fix, the optimized read_parquet code path will fail when the pandas metadata includes index-column information. It may also fail when the data includes list or struct columns (depending on the engine that wrote the parquet file).

[codecov]

Codecov Report

Merging #9638 (77807e7) into branch-21.12 (ab4bfaa) will decrease coverage by 0.09%.
The diff coverage is n/a.

❗ Current head 77807e7 differs from pull request most recent head 75e3fb6. Consider uploading reports for the commit 75e3fb6 to get more accurate results

@@               Coverage Diff                @@
##           branch-21.12    #9638      +/-   ##
================================================
- Coverage         10.79%   10.69%   -0.10%     
================================================
  Files               116      117       +1     
  Lines             18869    19849     +980     
================================================
+ Hits               2036     2123      +87     
- Misses            16833    17726     +893     

Impacted Files	Coverage Δ
python/dask_cudf/dask_cudf/sorting.py	92.90% <0.00%> (-1.21%)	⬇️
python/cudf/cudf/io/csv.py	0.00% <0.00%> (ø)
python/cudf/cudf/io/hdf.py	0.00% <0.00%> (ø)
python/cudf/cudf/io/orc.py	0.00% <0.00%> (ø)
python/cudf/cudf/__init__.py	0.00% <0.00%> (ø)
python/cudf/cudf/_version.py	0.00% <0.00%> (ø)
python/cudf/cudf/core/abc.py	0.00% <0.00%> (ø)
python/cudf/cudf/api/types.py	0.00% <0.00%> (ø)
python/cudf/cudf/io/dlpack.py	0.00% <0.00%> (ø)
python/cudf/cudf/core/frame.py	0.00% <0.00%> (ø)
... and 67 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3280be2...75e3fb6. Read the comment docs.

[rjzamora]

@gpucibot merge