[Python] Generate idiomatic except clauses for typed exception patterns

[dbrattli]

• Improves Python code generation for F# try-with expressions that use typed exception patterns. Instead of generating a single except BaseException with isinstance checks, we now generate separate except clauses for each exception type.
• Support catching Python BaseException subclasses (KeyboardInterrupt, SystemExit, GeneratorExit) for Python interop

Before:

try:
    run_synchronously(main_async)
except BaseException as match_value:
    if isinstance(match_value, KeyboardInterrupt):
        result = "keyboard"
    elif isinstance(match_value, ArgumentException):
        result = "argument"
    else:
        result = "other"

After:

try:
    run_synchronously(main_async)
except KeyboardInterrupt as match_value:
    result = "keyboard"
except ArgumentException as match_value:
    result = "argument"
except BaseException as match_value:
    result = "other"