Read list field correctly in <struct<list>>

[alamb]

Note: migrated from original JIRA: https://issues.apache.org/jira/browse/ARROW-11294

I noticed that when reading <struct<list>>, we overwrite the list's field name with the struct's one.

If we have a struct called "a", and a list called "items", the list gets the name "a", which is incorrect. See the test case called "arrow::arrow_writer::tests::arrow_writer_complex", which produces this behaviour. The test will be merged as part of ARROW-10766.