fix(tron): flaky tron-sdk build from cached build:tron outputs

[paulbalaji]

Summary

• make solidity/build-tron.sh clear cache-tron and generated Tron SDK output dirs before compiling
• this forces deterministic ABI/typechain generation for the @hyperlane-xyz/core#build:tron turbo task

Root cause

• @hyperlane-xyz/tron-sdk depends on @hyperlane-xyz/core#build:tron
• in a cache-hit path, restored/generated Tron typechain output could be incomplete (index/re-export files existed while many leaf files were missing)
• then tron-sdk TypeScript compile failed with many TS2307 Cannot find module ... errors in src/typechain/**

Verification

• reproduced failure with:
  • pnpm -C typescript/tron-sdk clean
  • pnpm turbo run build --filter=@hyperlane-xyz/tron-sdk --output-logs=full
• after fix, same command succeeds
• repeated the command again through cache-hit path; still succeeds

---

Note

Low Risk
Small build-script change that only affects generated artifacts and cache behavior; main risk is longer builds or unintended cleanup of expected outputs.

Overview
Makes the Tron Solidity build deterministic under Turbo cache hits by clearing incremental Hardhat/TypeChain state and generated outputs before compiling.

solidity/build-tron.sh now removes ./cache-tron plus the generated typescript/tron-sdk/src/abi and src/typechain directories up front, preventing partial/leftover trees from causing downstream tron-sdk TypeScript build failures.

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[paulbalaji]

rolled into #8205 (review)