refactor(core): replace transmute with MaybeUninit::array_assume_init

There is one potential use case that was overlooked by commit
`61a5f2838`.

Author: yvt

src/r3_core/src/bind.rs

@@ -1849,7 +1849,8 @@ where
                 );
                 i += 1;
             }
-            crate::utils::mem::transmute(out)
+            // Safety: All elements of `out` are initialized
+            MaybeUninit::array_assume_init(out)
         }
     }
 }