Prevent attempting to convert annoyingapi_converted key

For PDC 1.14+ in `EntityData#convertOldData(...)`

src/main/java/xyz/srnyx/annoyingapi/data/EntityData.java

@@ -27,6 +27,10 @@ public class EntityData extends StringData {
      * The name of the table in the database to store entity data
      */
     @NotNull public static final String TABLE_NAME = "entities";
+    /**
+     * The name of the key for the converted key (1.14+ only)
+     */
+    @NotNull private static final String CONVERTED_KEY = "annoyingapi_converted";
 
     /**
      * The entity to manage data for (only used for {@link #convertOldData(boolean, Collection)})
@@ -47,7 +51,7 @@ public EntityData(@NotNull AnnoyingPlugin plugin, @NotNull Entity entity) {
     /**
      * Convert all data from the old data storage system (PDC/file) to the new one (SQL)
      * <br>This <b>does not</b> run automatically, you must call this method manually (for example, on {@link org.bukkit.event.player.PlayerJoinEvent PlayerJoinEvent})!
-     * <br>For 1.14+ (PDC), the entity will receive the {@code api_converted} key which indicates that the data has been converted, this will avoid duplicate conversion checks
+     * <br>For 1.14+ (PDC), the entity will receive the {@link #CONVERTED_KEY} key which indicates that the data has been converted, this will avoid duplicate conversion checks
      * <br>All old data (PDC/file) will be removed after conversion (to avoid duplicate/overwriting data)
      *
      * @param   onlyTryOnce 1.14+ only | {@code true} to only try once to convert the data, even if it fails (so if run again, nothing will happen). If {@code false}, the conversion failed previously, and this is run again, it will try to convert again. If the data is successfully converted, this option doesn't matter
@@ -65,7 +69,7 @@ public Map<String, String> convertOldData(boolean onlyTryOnce, @Nullable Collect
                 // Get PDC
                 persistentDataContainer = PERSISTENT_DATA_HOLDER_GET_PERSISTENT_DATA_CONTAINER_METHOD.invoke(entity);
                 // Check if already converted
-                convertedKey = NAMESPACED_KEY_CONSTRUCTOR.newInstance(plugin, "annoyingapi_converted");
+                convertedKey = NAMESPACED_KEY_CONSTRUCTOR.newInstance(plugin, CONVERTED_KEY);
                 if (PERSISTENT_DATA_CONTAINER_GET_METHOD.invoke(persistentDataContainer, convertedKey, PERSISTENT_DATA_TYPE_BYTE) != null) return Collections.emptyMap();
                 // Set converted key if onlyTryOnce is true
                 if (onlyTryOnce) PERSISTENT_DATA_CONTAINER_SET_METHOD.invoke(persistentDataContainer, convertedKey, PERSISTENT_DATA_TYPE_BYTE, (byte) 1);
@@ -84,7 +88,7 @@ public Map<String, String> convertOldData(boolean onlyTryOnce, @Nullable Collect
                         final String namespace = (String) NAMESPACED_KEY_GET_NAMESPACE_METHOD.invoke(namespacedKey);
                         if (!pluginName.equals(namespace.toLowerCase())) continue;
                         final String key = (String) NAMESPACED_KEY_GET_KEY_METHOD.invoke(namespacedKey);
-                        namespacedKeys.put(key, namespacedKey);
+                        if (!key.equals(CONVERTED_KEY)) namespacedKeys.put(key, namespacedKey);
                     }
                 } catch (final ReflectiveOperationException e) {
                     sendError("convert", e);