Update to Minecraft 26.2

[eclipseisoffline]

This PR updates the mod to Minecraft 26.2 (currently release candidate 2). With this update, the mod moves to use Fabric API's new permissions API, which uses Minecraft's identifiers as permission nodes.

Permission managers like LuckPerms "flatten" these identifiers into a string by replacing the : with a .. For example, essentialcommands:tpa turns into essentialcommands.tpa. As such, the user-facing permission strings when using LuckPerms should remain unchanged.

Unsure on how to address the failing tests at the moment.

[John-Paul-R]

Thanks for the upgrade! I'll review today.

[arnokeesman]

tests also seem to run fine if I don't update gradle and loom, so guess there's some gradle hell ahead
succesful tests on a minimal update: https://github.com/arnokeesman/Essential-Commands/actions/runs/27651159484

[John-Paul-R]

currently worried this is going to use the mod_id (which is essential_commands) as the permissions namespace by default (instead of essentialcommands, which it has been to this point). if it does, then this will be a breaking permissions change for all users. I may need to shim in a fix to avoid that.

nevermind, I simply failed to read. Huzzah!

    public static Identifier of(String name) {
        return Identifier.fromNamespaceAndPath("essentialcommands", name);
    }

[John-Paul-R]

Looks good to me. Thank you!