Fix Qt6 deprecated APIs: QCheckBox::checkStateChanged, ExploratoryLocationViewshed

- Replace QCheckBox::stateChanged with checkStateChanged in:
  - lts_dialog.cpp
  - simple_esri_layer.cpp (2 occurrences)
  - layer_control_widget.cpp
  - symbol_dialog.cpp
- Replace LocationViewshed with ExploratoryLocationViewshed (ArcGIS SDK v300):
  - viewshed_analysis.h/.cpp
  - ViewshedLocation.h/.cpp
  - function_dialog.cpp (include)
- Update ViewshedLocation member variable type to ExploratoryLocationViewshed

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

qt6-after/qt6-migrated-legatus/external/include/KF6/KTextTemplate/ktexttemplate/variable.h

@@ -0,0 +1,118 @@
+/*
+  This file is part of the KTextTemplate library
+
+  SPDX-FileCopyrightText: 2009, 2010 Stephen Kelly <steveire@gmail.com>
+
+  SPDX-License-Identifier: LGPL-2.1-or-later
+
+*/
+
+#ifndef KTEXTTEMPLATE_VARIABLE_H
+#define KTEXTTEMPLATE_VARIABLE_H
+
+#include "ktexttemplate_export.h"
+
+#include <QVariant>
+
+namespace KTextTemplate
+{
+class Context;
+
+class VariablePrivate;
+
+/// @headerfile variable.h <KTextTemplate/Variable>
+
+/**
+  @brief A container for static variables defined in Templates.
+
+  This class is only relevant to Template tag authors.
+
+  When processing a template tag in a AbstractNodeFactory implementation, it
+  will sometimes make sense to process arguments to the tag as
+  KTextTemplate::Variables. Note that usually they should be processed as
+  FilterExpression objects instead.
+
+  Arguments to the tag can be used to construct Variables, which may then be
+  resolved into the objects they represent in the given Context in the render
+  stage.
+
+  @author Stephen Kelly <steveire@gmail.com>
+*/
+class KTEXTTEMPLATE_EXPORT Variable
+{
+public:
+    /**
+      Constructs an invalid **%Variable**
+    */
+    Variable();
+
+    /**
+      Creates a **%Variable** represented by the given @p var
+    */
+    explicit Variable(const QString &var);
+
+    /**
+      Copy constructor
+    */
+    Variable(const Variable &other);
+
+    /**
+      Destructor
+    */
+    ~Variable();
+
+    /**
+      Assignment operator.
+    */
+    Variable &operator=(const Variable &other);
+
+    /**
+      Returns whether this **%Variable** is valid.
+    */
+    bool isValid() const;
+
+    /**
+      Returns whether this **%Variable** evaluates to true with the Context @p c.
+    */
+    bool isTrue(Context *c) const;
+
+    /**
+      Resolves this **%Variable** with the Context @p c.
+    */
+    QVariant resolve(Context *c) const;
+
+    /**
+      Returns whether this **%Variable** is a constant in the Template. A constant
+      is represented as a static string in the template
+
+      @code
+        Text content
+        {% some_tag "constant" variable %}
+      @endcode
+    */
+    bool isConstant() const;
+
+    /**
+      Returns whether this variable is localized, that is, if it is wrapped with
+      _(). @see @ref i18n_l10n
+     */
+    bool isLocalized() const;
+
+    /**
+      Returns whether this variable is a literal string or number. A
+      literal **%Variable** does not have any lookup components.
+     */
+    QVariant literal() const;
+
+    /**
+      Returns the lookup components of this **%Variable**.
+     */
+    QStringList lookups() const;
+
+private:
+    Q_DECLARE_PRIVATE(Variable)
+    VariablePrivate *const d_ptr;
+};
+}
+
+#endif