Westend Assethub: Run State trie migration

[bkchr]

It looks like we never have run the state trie migration on Westend AssetHub. This means we can for example not warp sync the chain right now.

See polkadot-fellows/runtimes#74 for information on how this was done on the production networks.

[bkchr]

@nkpar could you take care to handle this for Westend AssetHub as well? As you also have done in for the production runtimes.