Bridges - revert-back congestion mechanism (#6781)

Closes: https://github.com/paritytech/polkadot-sdk/issues/5551

## Description

With [permissionless lanes
PR#4949](https://github.com/paritytech/polkadot-sdk/pull/4949), the
congestion mechanism based on sending
`Transact(report_bridge_status(is_congested))` from
`pallet-xcm-bridge-hub` to `pallet-xcm-bridge-hub-router` was replaced
with a congestion mechanism that relied on monitoring XCMP queues.
However, this approach could cause issues, such as suspending the entire
XCMP queue instead of isolating the affected bridge. This PR reverts
back to using `report_bridge_status` as before.

## TODO
- [x] benchmarks
- [x] prdoc

## Follow-up

https://github.com/paritytech/polkadot-sdk/pull/6231

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Co-authored-by: GitHub Action <action@github.com>
Co-authored-by: command-bot <>
Co-authored-by: Adrian Catangiu <adrian@parity.io>