Unable to build on system without Java21 installed

[rcd27]

How to reproduce: remove JVM_21 on your machine, run gradle sync.
I've fixed that by removing all jvmToolchains from gradle.plugins conventions. Seems like the build is working now.

[CharlieTap]

Hey thanks for submitting this, its something I forgot to configure now I'm making this public. The Gradle toolchains config is actually quite important for me as it allows me to remove one of the many variables (The build JDK) when debugging issues. Instead what I'll do is add id("org.gradle.toolchains.foojay-resolver-convention") to the settings.gradle.kts as a plugin, and this will download the required JDK on the fly as part of the build