Remove withDisallowUnsafeRead from PaperweightUserExtension#minecraftVersion

This is ok to read during configuration, as long as it's after the dev bundle dependency is set.

paperweight-userdev/src/main/kotlin/io/papermc/paperweight/userdev/PaperweightUserExtension.kt

@@ -81,5 +81,5 @@ abstract class PaperweightUserExtension(
      */
     val minecraftVersion: Provider<String> = objects.property<String>().value(
         setup.map { it.minecraftVersion }
-    ).withDisallowChanges().withDisallowUnsafeRead()
+    ).withDisallowChanges()
 }