Decommission edition worker lambdas

[akash1810]

Within the notification-sender-workers-cdk-<STAGE> CloudFormation stack there are two lambdas relating to the Editions product: ios-edition and android-edition. They are triggered via an SQS queue.

The metrics for the lambdas suggest they have not been invoked. Indeed, the SQS metrics indicate no messages have been written to the queue:

Can we decommission these lambdas? I think the easiest way to do this would be to:

1. Remove their instantiation within the cdk project
2. Remove the case objects and related code until the project compiles