fix: only remove empty tasks

Signed-off-by: Florian Reuth <git@florianreuth.de>

Author: florianreuth

Core/src/main/java/com/plotsquared/core/database/SQLManager.java

@@ -562,12 +562,8 @@ public synchronized boolean sendBatch() {
                     this.connection.setAutoCommit(true);
                 }
             }
-            if (!this.clusterTasks.isEmpty()) {
-                this.clusterTasks.clear();
-            }
-            if (!this.plotTasks.isEmpty()) {
-                this.plotTasks.clear();
-            }
+            this.clusterTasks.entrySet().removeIf(e -> e.getValue().isEmpty());
+            this.plotTasks.entrySet().removeIf(e -> e.getValue().isEmpty());
         } catch (Throwable e) {
             LOGGER.error("============ DATABASE ERROR ============");
             LOGGER.error("There was an error updating the database.");