fix: pass url as keyword argument to requests.post

[sentry]

The KeyError: 'url' occurred in repro.py because the post() helper in codecov_cli/helpers/request.py was calling requests.post with the url as a positional argument. When mocking requests.post, this meant url was in call_args[0] (positional arguments) but not in call_kwargs (keyword arguments).

The repro.py script's logic c.kwargs["url"] if c.kwargs else c.args[0] would then fail if c.kwargs was non-empty (which it was, containing json, headers, params) but did not contain a url key.

This change modifies the post() helper to explicitly pass url=url as a keyword argument to requests.post. This ensures that url is always available in c.kwargs when requests.post is mocked, resolving the KeyError and making mock introspection more consistent.

Fixes CLI-H6

_{This PR was automatically generated by Sentry. You can adjust this setting at any time.}

[codecov]

❌ 1 Tests Failed:

Tests completed	Failed	Passed	Skipped
723	1	722	1

View the full list of 1 ❄️ flaky test(s)

api.temp.calculator.test_calculator::test_divide

Flake rate in main: 100.00% (Passed 0 times, Failed 1726 times)

Stack Traces | 0.001s run time

def
                test_divide():
                > assert Calculator.divide(1, 2) == 0.5
                E assert 1.0 == 0.5
                E + where 1.0 = <function Calculator.divide at 0x104c9eb90>(1, 2)
                E + where <function Calculator.divide at 0x104c9eb90> = Calculator.divide
                .../temp/calculator/test_calculator.py:30: AssertionError

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