gh-50333: Deprecate support of non-tuple sequences in PyArg_ParseTuple() (GH-128374)

Non-tuple sequences are deprecated as argument for the "(items)" format unit
in PyArg_ParseTuple() and other argument parsing functions if items contains
format units which store borrowed buffer or reference (e.g. "s" and "O").

str and bytearray are no longer accepted as valid sequences.