feat(SqlLab): Change Save Dataset Button to Split Save Query Button IV (#20852)

* Moving entire split save btn PR

* Addressed review comments

* Remove arbitrary div from ErrorBoundary in Chart

* Added accidentally removed comment

* Fix act errors in SaveQuery tests

* Fix SaveDatasetActionButton test

* SaveDatasetModal test almost working

* SaveDatasetModal tests all passing

* Clean SaveDatasetModal test

* Fix create chart button and SaveDatasetModal text in SQL Lab

* Fix untitled dataset name on SaveDatasetModal in explore

* Fix styling on split save button

superset-frontend/src/SqlLab/components/SaveDatasetActionButton/SaveDatasetActionButton.test.tsx

@@ -0,0 +1,62 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+import React from 'react';
+import { render, screen } from 'spec/helpers/testing-library';
+import userEvent from '@testing-library/user-event';
+import { Menu } from 'src/components/Menu';
+import SaveDatasetActionButton from 'src/SqlLab/components/SaveDatasetActionButton';
+
+const overlayMenu = (
+  <Menu>
+    <Menu.Item>Save dataset</Menu.Item>
+  </Menu>
+);
+
+describe('SaveDatasetActionButton', () => {
+  it('renders a split save button', () => {
+    render(
+      <SaveDatasetActionButton
+        setShowSave={() => true}
+        overlayMenu={overlayMenu}
+      />,
+    );
+
+    const saveBtn = screen.getByRole('button', { name: /save/i });
+    const caretBtn = screen.getByRole('button', { name: /caret-down/i });
+
+    expect(saveBtn).toBeVisible();
+    expect(caretBtn).toBeVisible();
+  });
+
+  it('renders a "save dataset" dropdown menu item when user clicks caret button', () => {
+    render(
+      <SaveDatasetActionButton
+        setShowSave={() => true}
+        overlayMenu={overlayMenu}
+      />,
+    );
+
+    const caretBtn = screen.getByRole('button', { name: /caret-down/i });
+    userEvent.click(caretBtn);
+
+    const saveDatasetMenuItem = screen.getByText(/save dataset/i);
+
+    expect(saveDatasetMenuItem).toBeInTheDocument();
+  });
+});