Add gt_eq_dyn_utf8_scalar kernel and tests

[matthewmturner]

Which issue does this PR close?

Closes #1113 task gt_eq_dyn_utf8_scalar

Rationale for this change

What changes are included in this PR?

Are there any user-facing changes?

[codecov-commenter]

Codecov Report

Merging #1124 (ca93de7) into master (0d825c1) will increase coverage by 0.00%.
The diff coverage is 87.09%.

@@           Coverage Diff           @@
##           master    #1124   +/-   ##
=======================================
  Coverage   82.32%   82.32%           
=======================================
  Files         168      168           
  Lines       49577    49608   +31     
=======================================
+ Hits        40812    40839   +27     
- Misses       8765     8769    +4     

Impacted Files	Coverage Δ
arrow/src/compute/kernels/comparison.rs	90.75% <87.09%> (-0.13%)	⬇️
parquet_derive/src/parquet_field.rs	65.98% <0.00%> (-0.46%)	⬇️
arrow/src/array/transform/mod.rs	85.69% <0.00%> (+0.13%)	⬆️
arrow/src/datatypes/datatype.rs	66.80% <0.00%> (+0.42%)	⬆️

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[alamb]

Suggested change

	/// Perform `left >= right` operation on an array and a numeric scalar
	/// value. Supports StringArrays, and DictionaryArrays that have string values
	/// Perform `left >= right` operation on an array and a `str`
	/// value. Supports StringArrays, and DictionaryArrays that have string values

[alamb]

actually, to minimize how long this stuff is outstanding, I'll just merge the PRs and then do a final pass through to verify the text and errors

[alamb]

Thanks @matthewmturner