svx a11y: Switch to override new extended attr helper

Override the OAccessible::implGetExtendedAttributes
base class method newly introduced in

    Change-Id: Ie66f135fbf6cdc98c7cdca27fa3f5fe7db7f9a74
    Author: Michael Weghorn <m.weghorn@posteo.de>
    Date:   Thu Mar 5 12:12:45 2026 +0100

        a11y: Introduce helper to implement XAccessibleExtendedAttributes logic

instead of manually implementing
XAccessibleExtendedAttributes::getExtendedAttributes, to
unify/deduplicate the string concatenation and locking logic
by having it implemented (only) in the base class implementation.

Change-Id: I0a16552643c4a04c09df5b1129d55d96ebb0ee8e
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/201036
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>
Tested-by: Jenkins

include/svx/AccessibleShape.hxx

@@ -127,8 +127,6 @@ public:
     virtual void SAL_CALL deselectAccessibleChild(
         sal_Int64 nSelectedChildIndex ) override;
 
-    // ====== XAccessibleExtendedAttributes =====================================
-    virtual OUString SAL_CALL getExtendedAttributes() override;
     /// Return this object's role.
     virtual sal_Int16 SAL_CALL getAccessibleRole() override;
     //=====  XAccessibleGroupPosition  =========================================
@@ -217,6 +215,7 @@ public:
 
     // OAccessible
     virtual css::awt::Rectangle implGetBounds() override;
+    virtual std::unordered_map<OUString, OUString> implGetExtendedAttributes() override;
 
     //=====  XAccessibleComponent  ============================================
 

svx/source/accessibility/AccessibleShape.cxx

@@ -730,16 +730,15 @@ void SAL_CALL AccessibleShape::deselectAccessibleChild( sal_Int64 )
 
 }
 
-// XAccessibleExtendedAttributes
-OUString SAL_CALL AccessibleShape::getExtendedAttributes()
+std::unordered_map<OUString, OUString> AccessibleShape::implGetExtendedAttributes()
 {
     if (getAccessibleRole() != AccessibleRole::SHAPE)
-        return OUString();
+        return {};
 
     if (m_pShape)
-        return "style:" + GetStyle() + ";";
+        return { { u"style"_ustr, GetStyle() } };
 
-    return OUString();
+    return {};
 }
 
 // XTypeProvider