Don't explode on light data in the nether

It shouldn't be there but whatever

patches/server/0791-Rewrite-the-light-engine.patch

@@ -5040,7 +5040,7 @@ index 5ce6a2b83546f4dbc3183a386f51b4bacc173744..a7231ceda4f3e96c0e0c11eee953f129
          this.fluidTicks = fluidTickScheduler;
      }
 diff --git a/src/main/java/net/minecraft/world/level/chunk/storage/ChunkSerializer.java b/src/main/java/net/minecraft/world/level/chunk/storage/ChunkSerializer.java
-index be9c15fe141ede1132dbe07ba4bfcf22036ab194..b479c4a617becd3f31080ade0388c50727a56ba0 100644
+index be9c15fe141ede1132dbe07ba4bfcf22036ab194..4df5853781a2ac89dd391374d34d9096643a2ab8 100644
 --- a/src/main/java/net/minecraft/world/level/chunk/storage/ChunkSerializer.java
 +++ b/src/main/java/net/minecraft/world/level/chunk/storage/ChunkSerializer.java
 @@ -94,6 +94,14 @@ public class ChunkSerializer {
@@ -5136,7 +5136,7 @@ index be9c15fe141ede1132dbe07ba4bfcf22036ab194..b479c4a617becd3f31080ade0388c507
 +                    // is forced to re-light them if it encounters our data. It's too much of a burden
 +                    // to try and maintain compatibility with a broken and inferior skylight management system.
 +                    skyNibbles[y - minSection] = new ca.spottedleaf.starlight.common.light.SWMRNibbleArray(sectionData.getByteArray("SkyLight").clone(), sectionData.getInt(SKYLIGHT_STATE_TAG)); // clone for data safety
-+                } else {
++                } else if (flag1) {
 +                    skyNibbles[y - minSection] = new ca.spottedleaf.starlight.common.light.SWMRNibbleArray(null, sectionData.getInt(SKYLIGHT_STATE_TAG));
                  }
 +                // Paper end - rewrite the light engine