Requested URL is incorrect when PostHog host includes a path

[bcheidemann]

Version

3.17.0

Steps to Reproduce

1. Set com.posthog.posthog.POSTHOG_HOST to http://localhost:3000/some/path
2. Run a dummy server on port 3000 which logs incoming requests
3. Trigger a batch of events to be sent
4. Observe that the requested URL is http://localhost:3000/batch

Expected Result

The requested URL is http://localhost:3000/some/path/batch

Actual Result

The requested URL is http://localhost:3000/batch

Additional Context

See PostHog/posthog-flutter#128

[marandaneto]

Before closing this, I'd need to check if the same happens on Android and RN, good catch.