Cloud9 environment setup fails in an AWS account where Lambda Concurrent executions quota is low

[mabuchs]

In in AWS account where Lambda Concurrent executions quota is low, Cloud9 environment setup fails.
Root cause is error in creating C9BootstrapInstanceLambdaFunction and reason is below:

Resource handler returned message: "Specified ReservedConcurrentExecutions for function decreases account's UnreservedConcurrentExecution below its minimum value of [10]. (Service: Lambda, Status Code: 400, Request ID: 07097af1-64be-450d-9bf6-d2bc0701153d)" (RequestToken: feab4f82-17fa-ca88-2e9f-521cfe779f50, HandlerErrorCode: InvalidRequest)

Since AWS Lambda concurrency reservation requires 100 concurrencies for functions without reservation,
Setting ReservedConcurrentExecutions to 1 requires higher concurrency quota than 100.
In some accounts, initial quota is set to 10 therefore the setup fails.

cf.) https://docs.aws.amazon.com/lambda/latest/dg/configuration-concurrency.html

You can reserve up to the Unreserved account concurrency value minus 100. The remaining 100 units of concurrency are for functions that aren't using reserved concurrency. For example, if your account has a concurrency limit of 1,000, you cannot reserve all 1,000 units of concurrency to a single function.

Suggestion : I believe ReservedConcurrentExecutions property in C9BootstrapInstanceLambdaFunction can be removed since the actions in the Lambda function are idempotent.