test: fix failing test_simulate_succeeds on anvil@1.8.1

[0xNeshi]

Needed for #103, as it fixes its failing CI.

Cause

• The test workflow installs Foundry with no version input, so foundry-toolchain installs the current stable. The last green run on Aug 26 got anvil 1.7.1. The failing run on Sep 2 got anvil 1.8.1, released Aug 28.

• Foundry PR #15792 (in 1.8.0) makes anvil honor the validation: true flag of eth_simulateV1. It now enforces fee checks and returns the spec error codes -38010 to -38014.

• The test in tests/eth_namespace/call.rs:131-153 sends a call with no fee fields and validation: true. Anvil 1.8.1 answers:

  {"code":-38012,"message":"err: max fee per gas less than block base fee"}

• The robust provider treats this error as retryable in src/robust_provider/errors.rs:123, so it retries until the 5 second call timeout and reports Operation timed out. That hides the real error.