CloudWatch Logs should use a persistent log group

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**Tell us about your request**
App Runner presently creates unique log groups for each deployment event (the suffix to the service arn). This creates a few problems for us:
1. log group clutter, especially when deployments are frequent
2. lack of IaC control over data expiry
3. Inability to configure subscriptions during provisioning as log group names are unknown until after a deployment

**Describe alternatives you've considered**
The preferred solution is that a well known name is used per service (versus per deployment) such that subscriptions and configuration of the log groups is possible as part of IaC provisioning. Similar to what is presently done for both Lambda and ECS Fargate.

**Additional context**
n/a

**Attachments**
n/a

No repository files, tests, or entry points are named, and this is an AWS App Runner service request rather than a scoped code change. Start by reviewing the requested per-service persistent log-group behavior and its IaC implications; done means deployments no longer create deployment-specific groups and their names support expiry and subscription configuration.

Written by the indexing model from the issue text.