Mute Wiredash in widget tests

[passsy]

Don't call FlutterError.onError unless it is an error that can be resolved by the developer.

This came up in a 3rd party app testing setup. Test failed because the ping after 5s after app start tried to read the device information, but no mock was setup. Wiredash then called onError with the MissingPluginException.

Technically it could be fixed by mocking the plugin, but that is completely out of scope of the test. Wiredash can print the error, but should not fail the test.

• Check if pings and other jobs can be prevented altogether in 3rd party tests
• Check if not calling onWiredashInit() has negative consequences
  • Does not write firstAppStart and increment appStartCount (required for PromoterScore)
  • Does not send ping
  • Does not send pending feedbacks