'sharedApplication' is unavailable: not available on iOS (App Extension)

We've recently updated our One Signal installation which requires nesting the Notification Service Extension target inside the app target within the Podfile. This results in the following build errors from the Rollbar lib:

.../ios/Pods/Rollbar/KSCrash/Source/KSCrash/Reporting/Sinks/KSCrashReportSinkEMail.m:140:41: error build: 'sharedApplication' is unavailable: not available on iOS (App Extension) - Use view controller based solutions where appropriate instead.

.../ios/Pods/Rollbar/KSCrash/Source/KSCrash/Reporting/Sinks/KSCrashReportSinkEMail.m:250:31: error build: 'initWithTitle:message:delegate:cancelButtonTitle:otherButtonTitles:' is unavailable: not available on iOS (App Extension) - Use UIAlertController instead.

After contacting OneSignal, they've suggested that these errors could/should be warnings, and the installation is correct. We can get around the error by adding config.build_settings['APPLICATION_EXTENSION_API_ONLY'] = 'NO' to our post-install scripts in the Podfile.
Posting here in case anyone else needs this work-around, or Rollbar wants to consider this update to SDK

Start with KSCrash/Source/KSCrash/Reporting/Sinks/KSCrashReportSinkEMail.m in the Rollbar pod and inspect the reported locations around lines 140 and 250. Reproduce the build with the Notification Service Extension nested in the app target, then determine whether the extension build errors can be addressed without breaking the regular app target. Done means the reported extension build errors no longer occur.