Add entity API for getting the combined gene of a Panda (#9891)

patches/api/Missing-Entity-API.patch

@@ -705,6 +705,17 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +     */
 +    @Override
 +    boolean isSitting();
++
++    /**
++     * Gets this Panda's combined gene.
++     * <p>
++     * The combined gene can be modified using
++     * {@link #setMainGene(Gene)} or {@link #setHiddenGene(Gene)}.
++     *
++     * @return combined gene
++     */
++    @NotNull
++    Gene getCombinedGene();
 +    // Paper end - Panda API
 +
      public enum Gene {

patches/server/Missing-Entity-API.patch

@@ -850,9 +850,9 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 --- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPanda.java
 +++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPanda.java
 @@ -0,0 +0,0 @@ public class CraftPanda extends CraftAnimals implements Panda {
-     public void setHiddenGene(Gene gene) {
          this.getHandle().setHiddenGene(CraftPanda.toNms(gene));
      }
+ 
 +    // Paper start - Panda API
 +    @Override
 +    public void setSneezeTicks(int ticks) {
@@ -878,10 +878,16 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +    public void setUnhappyTicks(int ticks) {
 +        this.getHandle().setUnhappyCounter(ticks);
 +    }
++
++    @Override
++    public Gene getCombinedGene() {
++        return CraftPanda.fromNms(this.getHandle().getVariant());
++    }
 +    // Paper end - Panda API
- 
++
      @Override
      public boolean isRolling() {
+         return this.getHandle().isRolling();
 diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPhantom.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPhantom.java
 index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
 --- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPhantom.java