Add conditional rendering for toolbar header style options

The toolbar header style now has two possible displays. If the 'headerStyleType' configuration is set to 'isOriginal', the toolbar will exhibit 'QuillToolbarSelectHeaderStyleButtons'. Otherwise, it will show a dropdown menu 'QuillToolbarSelectHeaderStyleDropdownButton'. This adds flexibility to the UI of the toolbar.

lib/src/widgets/toolbar/simple_toolbar.dart

@@ -195,12 +195,20 @@ class QuillSimpleToolbar extends StatelessWidget
             color: configurations.sectionDividerColor,
             space: configurations.sectionDividerSpace,
           ),
-        if (configurations.showHeaderStyle)
+        if (configurations.showHeaderStyle) ...[
+          if (configurations.headerStyleType.isOriginal)
+            QuillToolbarSelectHeaderStyleButtons(
+              controller: globalController,
+              options:
+                  toolbarConfigurations.buttonOptions.selectHeaderStyleButtons,
+            )
+          else
             QuillToolbarSelectHeaderStyleDropdownButton(
               controller: globalController,
               options: toolbarConfigurations
                   .buttonOptions.selectHeaderStyleDropdownButton,
             ),
+        ],
         if (configurations.showDividers &&
             configurations.showHeaderStyle &&
             isButtonGroupShown[2] &&