Nerf placing down cellular blocks via Create means (#4532)

Block entity NBT is ignored when a cellular block is placed by a non-OP
player or by the various automated ways the Create mod has to offer.
That means cellular blocks placed in those ways always start at age
zero.

Xplat/src/main/java/vazkii/botania/common/block/block_entity/CellularBlockEntity.java

@@ -101,4 +101,9 @@ public void readPacketNBT(CompoundTag cmp) {
 		}
 	}
 
+	@Override
+	public boolean onlyOpCanSetNbt() {
+		// targeting Create here, sorry about any instances of https://xkcd.com/1172/
+		return true;
+	}
 }