[rejected AI] Fix BOOL conversion of 0 and 1

[Wahib294]

BOOL raises AttributeError: 'int' object has no attribute 'strip' when it
receives a number instead of a string. This happens for a boolean option with
default=1 or default=0, for a default_map loaded from a config file
where a boolean came through as a number, and for click.prompt(type=bool)
with a numeric default.

import click
click.BOOL(1)

Click 8.0 through 8.2.1 accepted 0 and 1 through the value in {False, True}
guard added in e79c2b4. #2956 (8.2.2) replaced it with isinstance(value, bool)
while reworking str_to_bool, so numbers now fall through to the string path.

This restores the guard and passes the value through str() before the
lookup, so 0 and 1 convert to False and True again and any other
non-string input produces the usual "is not a valid boolean" error instead of
a traceback.

fixes #3846

[davidism]

https://palletsprojects.com/contributing/llm-ai