[REVIEW] Fix some warnings in test_parquet.py

[galipremsagar]

Resolves part of #10363, there still are some warnings remaining, which I tried to resolve and went down a rabbit hole of a bug inside pyarrow<->pandas conversions so will take it up later.

[bdice]

I pushed one small commit to add a missing space to the warning string being caught here. I also have one suggestion for de-duplication of the warning handling logic. Either way, this looks good to me. Thanks!

[codecov]

Codecov Report

Merging #10416 (79be08c) into branch-22.04 (b613394) will increase coverage by 0.02%.
The diff coverage is 100.00%.

❗ Current head 79be08c differs from pull request most recent head 2019bad. Consider uploading reports for the commit 2019bad to get more accurate results

@@               Coverage Diff                @@
##           branch-22.04   #10416      +/-   ##
================================================
+ Coverage         86.13%   86.16%   +0.02%     
================================================
  Files               139      139              
  Lines             22460    22457       -3     
================================================
+ Hits              19347    19351       +4     
+ Misses             3113     3106       -7     

Impacted Files	Coverage Δ
python/cudf/cudf/io/parquet.py	92.70% <ø> (ø)
python/cudf/cudf/core/column/column.py	89.16% <100.00%> (+0.17%)	⬆️
python/cudf/cudf/core/dataframe.py	93.57% <100.00%> (ø)
python/cudf/cudf/core/frame.py	91.72% <100.00%> (ø)
python/cudf/cudf/core/single_column_frame.py	97.01% <100.00%> (ø)
python/cudf/cudf/core/column/string.py	88.39% <0.00%> (+0.12%)	⬆️
python/cudf/cudf/core/tools/datetimes.py	84.49% <0.00%> (+0.30%)	⬆️
python/cudf/cudf/core/groupby/groupby.py	91.92% <0.00%> (+0.43%)	⬆️
python/cudf/cudf/core/column/lists.py	90.56% <0.00%> (+0.47%)	⬆️

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[galipremsagar]

@gpucibot merge