scripts: drop isort --wrap-length 160 - it is broken with py3 and not really necessary

Under Python 3, isort 4.3.21 failed with
https://github.com/timothycrosley/isort/issues/741 on
kallithea/controllers/api/api.py :

Traceback (most recent call last):
File "data/env/bin/isort", line 10, in <module>
sys.exit(main())
File ".../env/lib64/python3.7/site-packages/isort/main.py", line 379, in main
for sort_attempt in attempt_iterator:
File ".../env/lib64/python3.7/site-packages/isort/main.py", line 377, in <genexpr>
attempt_iterator = (sort_imports(file_name, **arguments) for file_name in file_names)
File ".../env/lib64/python3.7/site-packages/isort/main.py", line 88, in sort_imports
result = SortImports(file_name, **arguments)
File ".../env/lib64/python3.7/site-packages/isort/isort.py", line 207, in __init__
self._add_formatted_imports()
File ".../env/lib64/python3.7/site-packages/isort/isort.py", line 606, in _add_formatted_imports
self._add_from_imports(from_modules, section, section_output, sort_ignore_case)
File ".../env/lib64/python3.7/site-packages/isort/isort.py", line 526, in _add_from_imports
import_statement = self._multi_line_reformat(import_start, from_import_section, comments)
File ".../env/lib64/python3.7/site-packages/isort/isort.py", line 552, in _multi_line_reformat
dynamic_indent, indent, line_length, comments)
File ".../env/lib64/python3.7/site-packages/isort/isort.py", line 705, in _output_grid
if len(next_statement.split(self.line_separator)[-1]) + 1 > line_length:
TypeError: '>' not supported between instances of 'int' and 'str'