remove migration method

Author: jakobhellermann

crates/bevy_ecs/src/world/mod.rs

@@ -115,13 +115,6 @@ impl World {
         InteriorMutableWorld::new(self)
     }
 
-    /// Creates a new [`InteriorMutableWorld`] with read+write access from a [&World](World).
-    /// This is only a temporary measure until every `&World` that is semantically a [`InteriorMutableWorld`]
-    /// has been replaced.
-    pub(crate) fn as_interior_mutable_migration_internal(&self) -> InteriorMutableWorld<'_> {
-        InteriorMutableWorld::new(self)
-    }
-
     /// Retrieves this world's [Entities] collection
     #[inline]
     pub fn entities(&self) -> &Entities {