(2026.06 and earlier) VDIs stuck in STOPPING state after auto stop is triggered

## Bug description
Virtual Desktops can get stuck in STOPPING state when idle timeout is reached for auto stop.
## Affected versions
* 2026.06 and earlier
## Mitigation

> **Tip:** We recommend running the following commands in [AWS CloudShell](https://console.aws.amazon.com/cloudshell/) in the same account and region where RES is deployed. CloudShell comes with pre-installed dependencies and helps eliminates other local environment conditions that may affect the patching process.

1. Update the memory for `-vdc-vdi-helper-lambda` lambda function from 128 MB to 512 MB by replacing the `` with the name of your RES environment in the comment below:
a. The mitigation requires [AWS CLI v2](https://docs.aws.amazon.com/cli/latest/userguide/getting-started-install.html)
b. Configure the AWS CLI for the account / region where RES is deployed.

```
aws lambda update-function-configuration \
--function-name -vdc-vdi-helper-lambda \
--memory-size 512
```

2. Verify that the memory size has been increased to 512 MB for `-vdc-vdi-helper-lambda` lambda function.

Start with the -vdc-vdi-helper-lambda function and reproduce an auto-stop at idle timeout in an affected 2026.06-or-earlier environment. Confirm the behavior and inspect the function's memory configuration; done means VDIs no longer remain in STOPPING after auto stop is triggered, with the mitigation's 512 MB setting verified.

Written by the indexing model from the issue text.