refactor(tron-wallet-snap): remove snap-owned asset abstractions

[ulissesferreira]

Summary

• Remove Tron Snap-owned asset abstractions and route standard asset reads through Core AssetsProvider.
• Update asset handlers and consumers toward Core asset fields.
• Remove local asset state deletion and update related configuration.

Validation

• Not fully verified. The branch contains known follow-up build and test issues from the migration handoff, including stale tests and incomplete price-service wiring.