Changes

saip SmspTpScAddr: safeguard against decoding error

Reading the TS48 V6.0 eSIM_GTP_SAIP2.1A_NoBERTLV profile results in an
exception [1] in SmspTpScAddr. I have a caller that needs to skip
erratic values instead of raising.

The underlying issue, I presume, is that either the data needs
validation before decode_record_bin(), or decode_record_bin() needs
well-defined error handling.

So far I know only of this IndexError, so, as a workaround, catch that.

[1]
  File "/pysim/pySim/esim/saip/personalization.py", line 617, in get_values_from_pes
    ef_smsp_dec = ef_smsp.decode_record_bin(f_smsp.body, 1)
  File "/pysim/pySim/filesystem.py", line 1047, in decode_record_bin
    return parse_construct(self._construct, raw_bin_data)
  File "/application/venv/lib/python3.13/site-packages/osmocom/construct.py", line 550, in parse_construct
    parsed = c.parse(raw_bin_data, total_len=length, **context)
  File "/application/venv/lib/python3.13/site-packages/construct/core.py", line 404, in parse
    return self.parse_stream(io.BytesIO(data), **contextkw)
           ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/application/venv/lib/python3.13/site-packages/construct/core.py", line 416, in parse_stream
    return self._parsereport(stream, context, "(parsing)")
           ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/application/venv/lib/python3.13/site-packages/construct/core.py", line 428, in _parsereport
    obj = self._parse(stream, context, path)
  File "/application/venv/lib/python3.13/site-packages/construct/core.py", line 2236, in _parse
    subobj = sc._parsereport(stream, context, path)
  File "/application/venv/lib/python3.13/site-packages/construct/core.py", line 428, in _parsereport
    obj = self._parse(stream, context, path)
  File "/application/venv/lib/python3.13/site-packages/construct/core.py", line 2770, in _parse
    return self.subcon._parsereport(stream, context, path)
           ~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
  File "/application/venv/lib/python3.13/site-packages/construct/core.py", line 428, in _parsereport
    obj = self._parse(stream, context, path)
  File "/application/venv/lib/python3.13/site-packages/construct/core.py", line 2236, in _parse
    subobj = sc._parsereport(stream, context, path)
  File "/application/venv/lib/python3.13/site-packages/construct/core.py", line 428, in _parsereport
    obj = self._parse(stream, context, path)
  File "/application/venv/lib/python3.13/site-packages/construct/core.py", line 2770, in _parse
    return self.subcon._parsereport(stream, context, path)
           ~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
  File "/application/venv/lib/python3.13/site-packages/construct/core.py", line 428, in _parsereport
    obj = self._parse(stream, context, path)
  File "/application/venv/lib/python3.13/site-packages/construct/core.py", line 820, in _parse
    return self._decode(obj, context, path)
           ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^
  File "/application/venv/lib/python3.13/site-packages/osmocom/construct.py", line 268, in _decode
    if r[-1] == 'f':
       ~^^^^
  File "/application/venv/lib/python3.13/site-packages/osmocom/utils.py", line 50, in __getitem__
    return hexstr(super().__getitem__(val))
                  ~~~~~~~~~~~~~~~~~~~^^^^^
IndexError: string index out of range

Change-Id: Ic436e206776b81f24de126e8ee0ae8bf5f3e8d7a