Function use_dual_stack_provider

pub async fn use_dual_stack_provider(
    provider_config: &ProviderConfig,
) -> Option<bool>

Load the value for “use dual-stack”

This checks the following sources:

1. The environment variable AWS_USE_DUALSTACK_ENDPOINT=true/false
2. The profile key use_dualstack_endpoint=true/false

If invalid values are found, the provider will return None and an error will be logged.