Uninitialized SalInstanceWidget::m_bKeyEventListener

Accidentally dropped with 492b0d5d "weld
conditional formatting"?  (Started to CppunitTest_dbaccess_tdf119625 in ASan/
UBSan builds like <https://ci.libreoffice.org/job/lo_ubsan/1269/>.)

Change-Id: I040b0eed9dd386b28674113b416e112c1666747b
Reviewed-on: https://gerrit.libreoffice.org/72267
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

vcl/source/app/salvtables.cxx

@@ -297,6 +297,7 @@ public:
         , m_pBuilder(pBuilder)
         , m_bTakeOwnership(bTakeOwnership)
         , m_bEventListener(false)
+        , m_bKeyEventListener(false)
         , m_bMouseEventListener(false)
         , m_nBlockNotify(0)
     {