fix(traces): decode expectRevert payload before revert formatting

[ArshLabs]

Motivation

expectRevert trace formatting currently feeds full cheatcode calldata into RevertDecoder, instead of decoding the cheatcode input first and passing only the expected-revert payload. This can produce misleading trace output.

Solution

Decode expectRevert inputs first in CallTraceDecoder::decode_cheatcode_inputs, then pass the decoded expected-revert bytes (bytes or bytes4) into RevertDecoder.

Added local decoder test coverage in the same module for:

• expectRevert(bytes4)
• expectRevert(bytes)
• expectRevert() fallback behavior

Validation performed:

• cargo +nightly fmt -- --check
• cargo test -p foundry-evm-traces
• cargo check --all
• cargo +nightly clippy -p foundry-evm-traces --all-targets -- -D warnings
• attempted cargo test --all --all-features (currently fails in this environment at tracy-client-sys, unrelated to touched code)

AI disclosure: I used AI assistance for basic code navigation, then did drafting & manually verified the implementation and test behavior.

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes