Resolves: tdf#78897 do not cache/reuse a repeat-filled string

Column widths or fonts or sizes may differ.

Change-Id: I1b4be9a6a6158e10439895534a8cb99c2ca408b7
(cherry picked from commit b94eccd1)
Reviewed-on: https://gerrit.libreoffice.org/19198Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

sc/source/ui/view/output2.cxx

@@ -509,6 +509,9 @@ bool ScDrawStringsVars::SetText( ScRefCellValue& rCell )
                     nChar = aString[ nPos + 1 ];
                     // delete placeholder and char to repeat
                     aString = aString.replaceAt( nPos, 2, "" );
+                    // Do not cache/reuse a repeat-filled string, column widths
+                    // or fonts or sizes may differ.
+                    maLastCell.clear();
                 }
             }
             else