feat(arrow-avro): accept default value of null for Avro union with null type in any branch position#9487

mzabaluev wants to merge 3 commits intoapache:mainapache/arrow-rs:mainfrom

mzabaluev:default-null-for-union-with-null-secondmzabaluev/arrow-rs:default-null-for-union-with-null-secondCopy head branch name to clipboard