Fix mismatched verification key in public key tests

[saiashok0981]

GitHub PR Description

### Summary
This PR fixes a bug in `test_public_keys` where `ecc_verify` was called with the wrong EC key (`ecc_key` instead of `ecc_key2`), causing verification failure and potential segmentation faults.

### Proposed Changes
- Modified `acl_lib/test_acl.cc` and `src/support_tests.cc` to use `ecc_key2` inside `ecc_verify` for the P-256 signature verification.