community/py3-commentjson: fix test

Fix failed test test_parse_constant that led to rebuild error (loongarch64 log).

ERROR: test_parse_constant (commentjson.tests.test_json.test_decode.TestCommentJsonDecode.test_parse_constant)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python3.12/site-packages/lark/lexer.py", line 673, in lex
    token = self.root_lexer.next_token(lexer_state, parser_state)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/lark/lexer.py", line 598, in next_token
    raise UnexpectedCharacters(lex_state.text, line_ctr.char_pos, line_ctr.line, line_ctr.column,
lark.exceptions.UnexpectedCharacters: No terminal matches 'I' in the current parser context, at line 1 col 1

Infinity
^
Expected one of: 
	* SIGNED_NUMBER
	* LSQB
	* TRUE
	* TRAILING_COMMA
	* LBRACE
	* NULL
	* ESCAPED_STRING
	* RBRACE
	* FALSE
	* COLON
	* RSQB