[protobuf] Add missing properties for class FieldDescriptor (#13625)

stubs/protobuf/google/protobuf/descriptor.pyi

@@ -156,6 +156,12 @@ class FieldDescriptor(DescriptorBase):
     cpp_type: Any
     @property
     def label(self): ...
+    @property
+    def camelcase_name(self) -> str: ...
+    @property
+    def has_presence(self) -> bool: ...
+    @property
+    def is_packed(self) -> bool: ...
     has_default_value: Any
     default_value: Any
     containing_type: Any