decidePolicyForNavigationResponse doesn't check that response is NSHTTPURLResponse

[jordoh]

When loading an HTML page from a bundled file (e.g. source={ { file: ... } }), the navigationResponse.response is not a NSHTTPURLResponse, which results in a SIGABRT when accessing the non-existent allHeaderFields property. This manifests (e.g. via crash reporting) as the following exception:

Application threw exception NSInternalInconsistencyException: Completion handler passed to -[RCTWKWebView webView:decidePolicyForNavigationResponse:decisionHandler:] was not called

I've tried passing onNavigationResponse={ null } to work around this, but _onNavigationResponse is still truthy even if I do, so the block in decidePolicyForNavigationResponse is still entered.

I'm happy to submit a PR to handle non-HTTP responses, given some guidance on what the desired handling would be. Should _onNavigationResponse be skipped in those cases, or called with different parameters? CC @DimitryDushkin

[insraq]

Should have been fixed with PR #195

[jordoh]

Great, thanks!