Revert unneeded isEmpty check in Edit::GetText

Introduced in commit 579cf9548615e8535a0569a8eb4cdf325fbbbac7
("tdf#138857 fix font replacement table GUI") to prevent a crash
in rtl_uString_newFromStr_WithLength (see the bugs comments),
neither sberg nor I could reproduce it, after I did a rebase and
full build. Maybe it happened because of a partial build after a
local rebase... no other idea.

Commit 8b66e1745933cd5aa4ae974f709a7e6c8be1f898 also added a unit
test, which passes.

This revert the change to Edit::GetText.

Change-Id: I1a178f912813b48b88b1c2e3831b9e1b7ab3717f
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/107690
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>
diff --git a/vcl/source/control/edit.cxx b/vcl/source/control/edit.cxx
index f631500..5699124 100644
--- a/vcl/source/control/edit.cxx
+++ b/vcl/source/control/edit.cxx
@@ -2577,12 +2577,7 @@ OUString Edit::GetText() const
    if ( mpSubEdit )
        return mpSubEdit->GetText();
    else
    {
        if (!maText.isEmpty())
            return maText.toString();
        else
            return OUString();
    }
        return maText.toString();
}

void Edit::SetCursorAtLast(){