(related tdf#154777) drawinglayer: add BBox to Figure fallback of forms

PAC3 complains if the BBox is missing.

Change-Id: I2cd61b2d01b64ffe77f28c661a3bd6f713df134f
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/154283
Tested-by: Jenkins
Reviewed-by: Michael Stahl <michael.stahl@allotropia.de>
diff --git a/drawinglayer/source/processor2d/vclmetafileprocessor2d.cxx b/drawinglayer/source/processor2d/vclmetafileprocessor2d.cxx
index eae5980..aba9444 100644
--- a/drawinglayer/source/processor2d/vclmetafileprocessor2d.cxx
+++ b/drawinglayer/source/processor2d/vclmetafileprocessor2d.cxx
@@ -1176,6 +1176,11 @@ void VclMetafileProcessor2D::processControlPrimitive2D(
    { // no corresponding PDF Form, use Figure instead
        mpPDFExtOutDevData->BeginStructureElement(vcl::PDFWriter::Figure);
        mpPDFExtOutDevData->SetStructureAttribute(vcl::PDFWriter::Placement, vcl::PDFWriter::Block);
        auto const range(rControlPrimitive.getB2DRange(getViewInformation2D()));
        tools::Rectangle const aLogicRect(
            basegfx::fround(range.getMinX()), basegfx::fround(range.getMinY()),
            basegfx::fround(range.getMaxX()), basegfx::fround(range.getMaxY()));
        mpPDFExtOutDevData->SetStructureBoundingBox(aLogicRect);
        OUString const& rAltText(rControlPrimitive.GetAltText());
        if (!rAltText.isEmpty())
        {