Revert "Enabling implicit output for generic bindings (#1348)" (#1376)

This reverts commit a981fcf.

Co-authored-by: root <root@GavinPC>

Author: gavin-aguiar

azure_functions_worker/bindings/generic.py

@@ -52,4 +52,4 @@ def decode(cls, data: datumdef.Datum, *, trigger_metadata) -> typing.Any:
 
     @classmethod
     def has_implicit_output(cls) -> bool:
-        return True
+        return False

tests/unittests/test_mock_generic_functions.py

@@ -131,7 +131,7 @@ async def test_mock_generic_should_not_support_implicit_output(self):
                              protos.StatusResult.Success)
 
             _, r = await host.invoke_function(
-                'foobar_implicit_output', [
+                'foobar_as_bytes_no_anno', [
                     protos.ParameterBinding(
                         name='input',
                         data=protos.TypedData(
@@ -140,10 +140,10 @@ async def test_mock_generic_should_not_support_implicit_output(self):
                     )
                 ]
             )
-            # It passes now as we are enabling generic binding to return output
-            # implicitly
+            # It should fail here, since generic binding requires
+            # $return statement in function.json to pass output
             self.assertEqual(r.response.result.status,
-                             protos.StatusResult.Success)
+                             protos.StatusResult.Failure)
 
     async def test_mock_generic_should_support_without_datatype(self):
         async with testutils.start_mockhost(
@@ -166,7 +166,7 @@ async def test_mock_generic_should_support_without_datatype(self):
                     )
                 ]
             )
-            # It passes now as we are enabling generic binding to return output
-            # implicitly
+            # It should fail here, since the generic binding requires datatype
+            # to be defined in function.json
             self.assertEqual(r.response.result.status,
-                             protos.StatusResult.Success)
+                             protos.StatusResult.Failure)