feat(interchain-token-service): encode source/recipient addresses as strings instead of XDR

[TanvirDeol]

AXE-7097

[TanvirDeol]

As of now, I have left the sender addresses in tests interchain_transfer_message_execute_succeeds and interchain_transfer_execute_succeeds as XDR format. This is because they get compared to previously recorded golden snapshots using the goldie crate.

Here is what I mean: goldie::assert!(events::fmt_last_emitted_event::<test::ExecutedEvent>(&env));

Changing these sender addresses to String format changes the bytes data representation which makes the assert fail.
Bytes when sender is String format: Bytes(0, 0, 0, 18, 0, 0, 0, ...),
Bytes when sender is XDR format: Bytes(67, 65, 65, 65, 65, ...),

So my question is: Should I change this golden snapshot data to fit the String format, or leave it as is?