[Rust] StreamReader, read_dictionary duplicating schema info

[asfimport]

The read_dictionary function takes both an ipc schema and a Schema, but it can get the information it needs from just the Schema. Then the StreamReader doesn't need to keep the ipc schema bytes around, because it also has the Schema.

The Flight integration test code needs to read dictionaries as well, and it seemed overly complex to need both kinds of schemas. PR coming!

Reporter: Carol Nichols / @carols10cents
Assignee: Carol Nichols / @carols10cents

PRs and other links:

• GitHub Pull Request #8820

_{Note: This issue was originally created as ARROW-10791. Please see the migration documentation for further details.}

[asfimport]

Neville Dipale / @nevi-me:
Issue resolved by pull request 8820
#8820