RTF import: change exception type thrown on destination errors

RTF import: change exception type thrown on destination errors

Previous exception (std::out_of_range) was not catch in case
of invalid RTF imported: wrapping code checks only for
uno::exception. This is not a case for loading file, but
for parsing of clipboard containing invalid RTF it was causing
fatal error, freeze and/or LO crash due to unhandled exception.

I think there is no reason to add generic processing for
std::exception in RTF filter: this can complicate diagnosing
other potential problems. Instead let's throw UNO exception,
like in other parts of RTF filter code.

Change-Id: I064bbdc1559cc7700c96dbbeaf2911a2c8e0421e
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/105285
Tested-by: Jenkins
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>