remove context

Author: hffmnn

packages/firebase_crashlytics/lib/src/firebase_crashlytics.dart

@@ -74,7 +74,6 @@ class Crashlytics {
       final dynamic result = await channel
           .invokeMethod<dynamic>('Crashlytics#onError', <String, dynamic>{
         'exception': "${exception.toString()}",
-        'context': 'onRuntimeException',
         'stackTraceElements': stackTraceElements,
         'logs': _logs.toList(),
         'keys': _prepareKeys(),

packages/firebase_crashlytics/test/firebase_crashlytics_test.dart

@@ -72,7 +72,7 @@ void main() {
       await crashlytics.onRuntimeException('foo exception', StackTrace.current);
       expect(log[0].method, 'Crashlytics#onError');
       expect(log[0].arguments['exception'], 'foo exception');
-      expect(log[0].arguments['context'], 'onRuntimeException');
+      expect(log[0].arguments['context'], null);
       expect(log[0].arguments['logs'], isNotEmpty);
       expect(log[0].arguments['logs'], contains('foo'));
       expect(log[0].arguments['keys'][0]['key'], 'testBool');