Design for incorrectly used retry attributes

Related: https://github.com/Azure/azure-functions-dotnet-worker/issues/1442, https://github.com/Azure/azure-functions-dotnet-worker/issues/1592

We need to define the behavior for the use of retry attributes on functions that do not support function-level retry. This behavior should be the same in both the loader extension and the source generator. Some options are:

1. Generate metadata with retry information and log a warning
2. Generate metadata but omit retry information and log a warning
3. Do not generate metadata for that function at all and log an error

Initial thought is that other functions without issues in the app should still be generated but that can also be discussed.