unotools a11y: Drop AccessibleRelationSetHelper::getImplementationId

It does the same as the WeakImplHelper base class
implementation.

Change-Id: I74b155d78c3f50fa5bf78dde7d3f738bbb952c3d
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/186750
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>

include/unotools/accessiblerelationsethelper.hxx

@@ -111,10 +111,6 @@ public:
     */
     virtual css::uno::Sequence<css::uno::Type> SAL_CALL getTypes() override;
 
-    /** Returns an implementation id.
-    */
-    virtual css::uno::Sequence<sal_Int8> SAL_CALL getImplementationId() override;
-
 private:
     /// Mutex guarding this object.
     mutable std::mutex maMutex;

unotools/source/accessibility/accessiblerelationsethelper.cxx

@@ -166,9 +166,4 @@ uno::Sequence< css::uno::Type> AccessibleRelationSetHelper::getTypes()
     return aTypes;
 }
 
-uno::Sequence<sal_Int8> SAL_CALL AccessibleRelationSetHelper::getImplementationId()
-{
-    return css::uno::Sequence<sal_Int8>();
-}
-
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */