Add more missing null checks to gui builder clone

Author: NichtStudioCode

invui-core/src/main/java/xyz/xenondevs/invui/gui/AbstractPagedGui.java

@@ -255,9 +255,9 @@ protected void applyModifiers(@NotNull PagedGui<C> gui) {
         @Override
         public @NotNull PagedGui.Builder<C> clone() {
             var clone = (AbstractBuilder<C>) super.clone();
-            if(this.content != null)
+            if (this.content != null)
                 clone.content = new ArrayList<>(this.content);
-            if(this.pageChangeHandlers != null)
+            if (this.pageChangeHandlers != null)
                 clone.pageChangeHandlers = new ArrayList<>(this.pageChangeHandlers);
             return clone;
         }

invui-core/src/main/java/xyz/xenondevs/invui/gui/AbstractScrollGui.java

@@ -257,8 +257,10 @@ protected void applyModifiers(@NotNull ScrollGui<C> gui) {
         @Override
         public @NotNull ScrollGui.Builder<C> clone() {
             var clone = (AbstractBuilder<C>) super.clone();
-            clone.content = new ArrayList<>(content);
-            clone.scrollHandlers = new ArrayList<>(scrollHandlers);
+            if (this.content != null)
+                clone.content = new ArrayList<>(content);
+            if (this.scrollHandlers != null)
+                clone.scrollHandlers = new ArrayList<>(scrollHandlers);
             return clone;
         }
 

invui-core/src/main/java/xyz/xenondevs/invui/gui/AbstractTabGui.java

@@ -26,8 +26,9 @@ public abstract class AbstractTabGui extends AbstractGui implements TabGui {
 
     /**
      * Creates a new {@link AbstractTabGui}.
-     * @param width The width of the gui.
-     * @param height The height of the gui.
+     *
+     * @param width     The width of the gui.
+     * @param height    The height of the gui.
      * @param tabAmount The amount of tabs.
      * @param listSlots The slots to be used for the content.
      */
@@ -39,8 +40,9 @@ public AbstractTabGui(int width, int height, int tabAmount, int... listSlots) {
 
     /**
      * Creates a new {@link AbstractTabGui}.
-     * @param width The width of the gui. 
-     * @param height The height of the gui.
+     *
+     * @param width     The width of the gui.
+     * @param height    The height of the gui.
      * @param tabAmount The amount of tabs.
      * @param structure The structure of the gui.
      */
@@ -164,8 +166,10 @@ protected void applyModifiers(@NotNull TabGui gui) {
         @Override
         public @NotNull TabGui.Builder clone() {
             var clone = (AbstractBuilder) super.clone();
-            clone.tabs = new ArrayList<>(tabs);
-            clone.tabChangeHandlers = new ArrayList<>(tabChangeHandlers);
+            if (tabs != null)
+                clone.tabs = new ArrayList<>(tabs);
+            if (tabChangeHandlers != null)
+                clone.tabChangeHandlers = new ArrayList<>(tabChangeHandlers);
             return clone;
         }