Move splitview toolbar buttons into a button menu

The buttons have very long labels, which made the window too wide
or caused the toolbar to display a disclosure button to show all the
options.

This moves those buttons into a "Split View" toolbar button, which
fixes those issues and looks much nicer.

BUG: 437555

desktop/konsoleui.rc

@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <!DOCTYPE gui SYSTEM "kpartgui.dtd">
 
-<gui name="konsole" version="17">
+<gui name="konsole" version="18">
     <MenuBar>
         <Menu name="file"><text>File</text>
             <Action name="new-window"/>
@@ -57,10 +57,6 @@
         <text>Main Toolbar</text>
         <index>0</index>
         <Action name="new-tab"/>
-        <Action name="split-view-left-right"/>
-        <Action name="split-view-top-bottom"/>
-        <Action name="load-terminals-layout-2x2"/>
-        <Action name="load-terminals-layout-2x1"/>
-        <Action name="load-terminals-layout-1x2"/>
+        <Action name="split-view"/>
     </ToolBar>
 </gui>

src/ViewManager.cpp

@@ -21,6 +21,7 @@
 
 // KDE
 #include <KActionCollection>
+#include <KActionMenu>
 #include <KConfigGroup>
 #include <KLocalizedString>
 #include <KMessageBox>
@@ -101,6 +102,11 @@ void ViewManager::setupActions()
     }
 
     KActionCollection *collection = _actionCollection;
+    KActionMenu *splitViewActions =
+        new KActionMenu(QIcon::fromTheme(QStringLiteral("view-split-left-right")), i18nc("@action:inmenu", "Split View"), collection);
+    splitViewActions->setPopupMode(QToolButton::InstantPopup);
+    collection->addAction(QStringLiteral("split-view"), splitViewActions);
+
     // Let's reuse the pointer, no need not to.
     auto *action = new QAction(this);
     action->setIcon(QIcon::fromTheme(QStringLiteral("view-split-left-right")));
@@ -108,6 +114,7 @@ void ViewManager::setupActions()
     connect(action, &QAction::triggered, this, &ViewManager::splitLeftRight);
     collection->addAction(QStringLiteral("split-view-left-right"), action);
     collection->setDefaultShortcut(action, Konsole::ACCEL | Qt::Key_ParenLeft);
+    splitViewActions->addAction(action);
 
     action = new QAction(this);
     action->setIcon(QIcon::fromTheme(QStringLiteral("view-split-top-bottom")));
@@ -115,6 +122,9 @@ void ViewManager::setupActions()
     connect(action, &QAction::triggered, this, &ViewManager::splitTopBottom);
     collection->setDefaultShortcut(action, Konsole::ACCEL | Qt::Key_ParenRight);
     collection->addAction(QStringLiteral("split-view-top-bottom"), action);
+    splitViewActions->addAction(action);
+
+    splitViewActions->addSeparator();
 
     action = new QAction(this);
     action->setIcon(QIcon::fromTheme(QStringLiteral("view-split-top-bottom")));
@@ -123,6 +133,7 @@ void ViewManager::setupActions()
         this->loadLayout(QStandardPaths::locate(QStandardPaths::GenericDataLocation, QStringLiteral("konsole/2x2-terminals.json")));
     });
     collection->addAction(QStringLiteral("load-terminals-layout-2x2"), action);
+    splitViewActions->addAction(action);
 
     action = new QAction(this);
     action->setIcon(QIcon::fromTheme(QStringLiteral("view-split-left-right")));
@@ -131,14 +142,16 @@ void ViewManager::setupActions()
         this->loadLayout(QStandardPaths::locate(QStandardPaths::GenericDataLocation, QStringLiteral("konsole/2x1-terminals.json")));
     });
     collection->addAction(QStringLiteral("load-terminals-layout-2x1"), action);
+    splitViewActions->addAction(action);
 
     action = new QAction(this);
     action->setIcon(QIcon::fromTheme(QStringLiteral("view-split-top-bottom")));
-    action->setText(i18nc("@action:inmenu", "Load a new tab with layout 2x1 terminals"));
+    action->setText(i18nc("@action:inmenu", "Load a new tab with layout 1x2 terminals"));
     connect(action, &QAction::triggered, this, [this]() {
         this->loadLayout(QStandardPaths::locate(QStandardPaths::GenericDataLocation, QStringLiteral("konsole/1x2-terminals.json")));
     });
     collection->addAction(QStringLiteral("load-terminals-layout-1x2"), action);
+    splitViewActions->addAction(action);
 
     action = new QAction(this);
     action->setText(i18nc("@action:inmenu", "Expand View"));