test(amm): keep required liquidity burn check priced

[decofe]

Summary

• Set an explicit priority fee on test_cant_burn_required_liquidity burn tx.
• Keeps the fee-swap reservation large enough under TIP-1067 dynamic base fees so the test continues to assert the intended invariant.

Why

The mutation coverage job failed in coverage with tip_fee_amm::test_cant_burn_required_liquidity: the burn receipt succeeded when the test expected it to fail. Under dynamic base fees, max_fee_per_gas alone can leave the tx with a lower effective gas price than the test assumed.

Verification

• cargo test -p tempo-node --test it tip_fee_amm::test_cant_burn_required_liquidity -- --nocapture
• cargo +nightly fmt --check