Read/Write nested dictionaries under FixedSizeList in IPC

[viirya]

Which issue does this PR close?

Closes #1609.

Rationale for this change

What changes are included in this PR?

Are there any user-facing changes?

[codecov-commenter]

Codecov Report

Merging #1610 (1706cf8) into master (fd9cb23) will increase coverage by 0.00%.
The diff coverage is 88.00%.

❗ Current head 1706cf8 differs from pull request most recent head f645b64. Consider uploading reports for the commit f645b64 to get more accurate results

@@           Coverage Diff           @@
##           master    #1610   +/-   ##
=======================================
  Coverage   82.95%   82.96%           
=======================================
  Files         193      193           
  Lines       55435    55460   +25     
=======================================
+ Hits        45988    46010   +22     
- Misses       9447     9450    +3     

Impacted Files	Coverage Δ
arrow/src/ipc/writer.rs	80.27% <62.50%> (-0.25%)	⬇️
arrow/src/ipc/reader.rs	89.43% <100.00%> (+0.26%)	⬆️

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[nevi-me]

LGTM

[viirya]

Thank you @nevi-me