Fix disabled relay chain XCM tests broken by AHM

[rockbmb]

With the Asset Hub Migration, which occurred on the 7th of October of 2025 in the Kusama network, some XCM tests between that relay chain and its parachains stopped working, and were temporarily disabled.

Examples:

polkadot-ecosystem-tests/packages/kusama/src/karura.kusama.test.ts

Lines 14 to 24 in d35064e

	runXtokensUp(
	'karura transfer KSM to kusama',
	async () => {
	return {
	fromChain: karuraClient,
	toChain: kusamaClient,
	balance: query.tokens(karuraKSM),
	tx: tx.xtokens.transfer(karuraKSM, 1e12, tx.xtokens.relaychainV3),
	}
	},
	{ skip: true },

polkadot-ecosystem-tests/packages/kusama/src/kusama.shiden.test.ts

Lines 27 to 37 in d35064e

	runXcmPalletDown(
	'kusama transfer KSM to shiden',
	async () => {
	return {
	fromChain: kusamaClient,
	toChain: shidenClient,
	balance: query.assets(shidenKSM),
	tx: tx.xcmPallet.limitedReserveTransferAssetsV3(kusamaKSM, 1e12, tx.xcmPallet.parachainV3(0, shiden.paraId!)),
	}
	},
	{ skip: true },

The same will happen on Polkadot after its AHM occurs (scheduled for the 4th of November); see branch polkadot-ahm for which Polkadot tests needed to be disabled during local testing.
- This is the branch that will be merged to master containing all post-AHM updates to Polkadot tests

This issue tracks the fixing of these XCM tests.

[rockbmb]

@xlc delayed, but here it is 👍

In the polkadot-ahm branch, I have already disabled the failing Polkadot XCM tests using a post-migration testing snapshot.
In this way, on the on the day of the migration, they won't break CI.