String model no longer supports semitransparency

As mentioned in the changelog of 26.1 snapshot 3, the tripwire texture now renders “as alpha cutout instead of transparent”. This is a significant breaking change for custom maps, which often used tripwire when making custom models for its unique combination of features (no collision, supports semitransparency). There are no other blocks that have both of these features, so this change results in lost functionality.