ExUnits calculation is wrong for validation rules

[agaffney]

We're seeing these validation failures:

{"time":"2025-04-21T18:16:24.406211877-04:00","level":"WARN","msg":"TX 3ace3bc7f4c5909187ff29a0dd6f27a4510b8456a8572cbd22c8efb8646a5e46 failed validation: ExUnits too big: total 5060693388/19936728 steps/memory, maximum 10000000000/14000000 steps/memory"}
...
{"time":"2025-04-21T18:39:20.418053999-04:00","level":"WARN","msg":"TX ca9bf9f3d708c22e3cc00d1ccce408de96c80bab71c037d516a94102fe7d579c failed validation: ExUnits too big: total 7786936475/16168138 steps/memory, maximum 10000000000/14000000 steps/memory"}
...
{"time":"2025-04-21T18:45:30.936198776-04:00","level":"WARN","msg":"TX 3c5468c0ddd9eaf016058ac7920fd1f53779e42984c81947c605d90e78988491 failed validation: ExUnits too big: total 7019861617/15149230 steps/memory, maximum 10000000000/14000000 steps/memory"}
...
{"time":"2025-04-21T18:45:32.419693246-04:00","level":"WARN","msg":"TX 561c39d2e8c30b9a947b187a3a284a9d1d72bdf091f95d6c606841a42c4bbb6a failed validation: ExUnits too big: total 6788662621/15203632 steps/memory, maximum 10000000000/14000000 steps/memory"}