Bridge Permissionless Lanes - more tests

[acatangiu]

Relates to #4949

We should also add emulated tests for:

• open + close lane
• open + traffic + close (with pending message) lane
• migration from static lane between AHs to dynamic one
• migration doesn't lose any in-flight messages

[bkontur]

* [ ]  open + close lane[ ] 

@rosarp let's start with first one. You need to build it on the top of this branch: bko-permlanes-on-ahs, anyway, please check that PR - it is about setting pallets for permissionless lanes on the AssetHubs. And the test should be like:

• AssetHubRococo::open_bridge(AssetHubWestendLocation)
• AssetHubWestend::open_bridge(AssetHubRococoLocation)
• check the events on both side, both should contain event BridgeOpened {lane_id}, where lane_id have to be the same
• AssetHubRococo::close_bridge(..)
• AssetHubWestend::close_bridge(..)
• again check BridgePruned event

Hints: https://github.com/paritytech/polkadot-sdk/blob/master/cumulus/parachains/integration-tests/emulated/tests/bridges/bridge-hub-rococo/src/tests/mod.rs#L244