Fix supporting fluid check for striders

[Nobodiiiii]

Vanilla striders lose their lava-surface collision support and move slowly with repeated stuttering when Sable is installed. LiquidBlock.getCollisionShape passes the fluid above the block as the first argument and the supporting fluid as the second argument to canStandOnFluid. Sable checks the first argument, so air above lava causes the capability check to fail.

Check fluidState2, matching vanilla EntityCollisionContext. This restores the lava support shape and prevents striders from repeatedly sinking into the buoyancy branch that halves their velocity. The change is limited to one argument; movement speed and buoyancy are unchanged.

Fixes #305.
Related reports: #811, #1285, #1389.

Validation

• Reproduced on Minecraft 1.21.1 with only Create, Create: Aeronautics, and their required dependencies, including Sable 2.0.5.
• Compiled the modified class with Java 21 and verified that the capability check receives the second argument.
• Tested a Sable 2.0.5 JAR containing only the recompiled replacement class; verified that every other archive entry was unchanged. In-game testing confirmed that the strider movement issue is fixed.
• A full repository Gradle build was not completed; the runtime validation used the existing 2.0.5 release JAR with that single class replaced.

[CLAassistant]

All committers have signed the CLA.