[Rust] Propagate custom_metadata field from IPC message #23558
Description
Right now, the custom metadata field in the Schema IPC message is not propagated from the IPC message to the internal data type. To be closer to parity compared to the other implementations it would be good to add the necessary logic to serialize and deserialize.
Reporter: Martin Grund
PRs and other links:
Note: This issue was originally created as ARROW-7268. Please see the migration documentation for further details.