Fix env var names in AWS ECS and Lambda executor setup docs (#76155)

The AWS console setup steps told users to set AIRFLOW__ECS_EXECUTOR__*
and AIRFLOW__LAMBDA_EXECUTOR__* variables, but the executors read the
aws_ecs_executor and aws_lambda_executor config sections. Airflow
silently ignored the documented variables, so ECS tasks started without
the security groups and subnets needed to reach the metadata database,
and the Lambda executor had no SQS queue URL.

providers/amazon/docs/executors/ecs-executor.rst

@@ -339,9 +339,9 @@ Create Task Definition
   :end-before: .. END SQL_ALCHEMY_CONN
 
 
-- ``AIRFLOW__ECS_EXECUTOR__SECURITY_GROUPS``, with the value being a comma separated list of security group IDs associated with the VPC used for the RDS instance.
+- ``AIRFLOW__AWS_ECS_EXECUTOR__SECURITY_GROUPS``, with the value being a comma separated list of security group IDs associated with the VPC used for the RDS instance.
 
-- ``AIRFLOW__ECS_EXECUTOR__SUBNETS``, with the value being a comma separated list of subnet IDs of the subnets associated with the RDS instance.
+- ``AIRFLOW__AWS_ECS_EXECUTOR__SUBNETS``, with the value being a comma separated list of subnet IDs of the subnets associated with the RDS instance.
 
 1. Add other configuration as necessary for Airflow generally (see `here <https://airflow.apache.org/docs/apache-airflow/stable/configurations-ref.html>`__), the ECS executor (see :ref:`here <config-options>`) or for remote logging (see :ref:`here <logging>`). Note that any configuration changes should be made across the entire Airflow environment to keep configuration consistent.
 

providers/amazon/docs/executors/lambda-executor.rst

@@ -357,7 +357,7 @@ Finally create the function:
   :end-before: .. END SQL_ALCHEMY_CONN
 
 
-- ``AIRFLOW__LAMBDA_EXECUTOR__QUEUE_URL``, with the value being the URL of the SQS queue created above.
+- ``AIRFLOW__AWS_LAMBDA_EXECUTOR__QUEUE_URL``, with the value being the URL of the SQS queue created above.
 
 7. Add other configuration as necessary for Airflow generally (see `here <https://airflow.apache.org/docs/apache-airflow/stable/configurations-ref.html>`__), the Lambda executor (see :ref:`here <lambda_config-options>`) or for remote logging (see :ref:`here <lamba_logging>`). Note that any configuration changes should be made across the entire Airflow environment to keep configuration consistent.