[Service Bus] Add recorded tests and re-enable the CI pipelines

## Summary

Every integration test in the crate is marked `#[recorded::test(live)]` and there is no `assets.json`. Nothing runs in CI without a live namespace, and the two `rust - servicebus` pipelines are disabled because they always failed.

## Motivation

`azure_messaging_eventhubs` ships an `assets.json` that points at `Azure/azure-sdk-assets`, so its tests replay against the test proxy. Service Bus has no equivalent, so its 56 integration tests give no signal on a pull request.

A crate cannot ship a stable release with no CI coverage. This is the gate that turns the rest of the graph from a claim into a verified one.

## Proposal

- Add an `assets.json` and record the test sessions against the test proxy.
- Convert the tests that do not need a live namespace to recorded playback, and keep the rest live.
- Re-enable the `rust - servicebus` and `rust - servicebus - weekly` pipelines.
- Add the performance harness that Event Hubs ships.

Closes #3431 when the pipelines are green.

## Dependencies

Blocked by:

- #4943 [Service Bus] Settlement sends the wrong AMQP outcomes and discards caller input

Sub-issue of #4934.

Start by comparing the Service Bus integration-test setup with azure_messaging_eventhubs, especially its assets.json and recorded test sessions. Record the eligible tests against the test proxy, keep namespace-dependent tests live, add the performance harness, and re-enable the two named rust - servicebus pipelines; done means both pipelines are green.

Written by the indexing model from the issue text.