Remove TakeFirstAssetTrader from AH Westend and Rococo

[x3c41a]

Description

Removed TakeFirstAssetTrader from Asset Hub Westend and Rococo. Improved macros, fixed tests.

This implies asset sufficiency no longer guarantees that weight can also be bought with it. SwapFirstAssetTrader is used instead which will attempt to swap some of the given asset for the required amount of native asset to buy weight. This may or may not succeed depending on whether there is a local pool present with enough liquidity to serve the swap.

Review notes

Additionally parametrised macro and fixed Westend test: weight swapping was failing at this line with around 100x difference thus had to modify the macro.

Fixes #8233

[x3c41a]

if it comes to
[Check publish build / check-publish-compile (pull_request)](https://github.com/paritytech/polkadot-sdk/actions/runs/14749062513/job/41402146630?pr=8376) failure, I ran cargo build -p parachain-template-node on my local machine and everything went well; might be unrelated to my change.

[x3c41a]

I modified runtime test.

1. I followed gut feeling and removed the tests which were testing take_first_trader functionality.
   Remove functionality --> remove its tests.
   Let me know in case I was wrong and we do need to keep those tests

2. Also, I fixed test_asset_xcm_take_first_trader_not_possible_for_non_sufficient_assets by adding liquidity pool and extra checks to it -- please verify the checks make sense

[franciscoaguirre]

It's fine to remove those tests. We no longer use sufficient assets for fee payment, we always use liquidity pools, and we have tests for using liquidity pools to swap for fee payment already

[paritytech-workflow-stopper]

All GitHub workflows were cancelled due to failure one of the required jobs.
Failed workflow url: https://github.com/paritytech/polkadot-sdk/actions/runs/14798317288
Failed job name: fmt