tdf#95091: enable delete and backspace in editable elements within protections

when editing is enabled also delete and backspace should be possible
this applies e.g. to input fields within protected sections

Change-Id: Iee5ef133971a3f2967e6c92e685a16afa003cfe8
Reviewed-on: https://gerrit.libreoffice.org/19399Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Oliver Specht <oliver.specht@cib.de>
(cherry picked from commit ac427caf)
Reviewed-on: https://gerrit.libreoffice.org/19453Reviewed-by: Björn Michaelsen <bjoern.michaelsen@canonical.com>
Tested-by: Björn Michaelsen <bjoern.michaelsen@canonical.com>

sw/source/uibase/docvw/edtwin.cxx

@@ -1822,7 +1822,7 @@ KEYINPUT_CHECKTABLE_INSDEL:
                     break;
 
                 case KEY_DELETE:
-                    if ( !rSh.HasReadonlySel() )
+                    if ( !rSh.HasReadonlySel() || rSh.CrsrInsideInputField())
                     {
                         if (rSh.IsInFrontOfLabel() && rSh.NumOrNoNum(false))
                             eKeyState = KS_NumOrNoNum;
@@ -1909,7 +1909,7 @@ KEYINPUT_CHECKTABLE_INSDEL:
                 break;
                 case KEY_BACKSPACE:
                 case KEY_BACKSPACE | KEY_SHIFT:
-                    if ( !rSh.HasReadonlySel() )
+                    if ( !rSh.HasReadonlySel() || rSh.CrsrInsideInputField())
                     {
                         bool bDone = false;
                         // try to add comment for code snip: