Create sections for chunk conversion if non-existant

Required to add in the new biome sections

patches/server/0781-Rewrite-dataconverter-system.patch

@@ -15313,10 +15313,10 @@ index 0000000000000000000000000000000000000000..d28ade80499dce882a9a84309a2a0da5
 +}
 diff --git a/src/main/java/ca/spottedleaf/dataconverter/minecraft/versions/V2832.java b/src/main/java/ca/spottedleaf/dataconverter/minecraft/versions/V2832.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..6a975a5e69f4aad4b65aaf1300b5136d72ea6499
+index 0000000000000000000000000000000000000000..b1049823fc2ff1c8183f4664ff4d40da6495f9ee
 --- /dev/null
 +++ b/src/main/java/ca/spottedleaf/dataconverter/minecraft/versions/V2832.java
-@@ -0,0 +1,919 @@
+@@ -0,0 +1,920 @@
 +package ca.spottedleaf.dataconverter.minecraft.versions;
 +
 +import ca.spottedleaf.dataconverter.converters.DataConverter;
@@ -15710,14 +15710,16 @@ index 0000000000000000000000000000000000000000..6a975a5e69f4aad4b65aaf1300b5136d
 +                final MapType<String>[] newBiomes = createBiomeSections(level, isOverworld, minSection, isAlreadyExtended);
 +                final MapType<String> wrappedEmptyBlockPalette = getEmptyBlockPalette();
 +
-+                final ListType sections = level.getList("Sections", ObjectType.MAP);
++                ListType sections = level.getList("Sections", ObjectType.MAP);
++                if (sections == null) {
++                    level.setList("Sections", sections = Types.NBT.createEmptyList());
++                }
 +
 +                // must update sections for two things:
 +                // 1. the biomes are now stored per section, so we must insert the biomes palette into each section (and create them if they don't exist)
 +                // 2. each section must now have block states (or at least DFU is ensuring they do, but current code does not require)
 +                V2841.SimplePaletteReader bottomSection = null;
 +                final Set<String> allBlocks = new HashSet<>();
-+                if (sections != null) {
 +                final IntOpenHashSet existingSections = new IntOpenHashSet();
 +
 +                for (int i = 0, len = sections.size(); i < len; ++i) {
@@ -15777,7 +15779,6 @@ index 0000000000000000000000000000000000000000..6a975a5e69f4aad4b65aaf1300b5136d
 +
 +                    newSection.setGeneric("biomes", newBiomes[sectionIndex]);
 +                }
-+                }
 +
 +                // update status so interpolation can take place
 +                predictChunkStatusBeforeSurface(level, allBlocks);