retry network interface deletion in case vm creation errors out

[fmoehler]

In case the vm fails to start up for some reason the network interface deletion is not retried. This could lead to errors like "IP address is already in use" on consecutive tries to create the vm (bosh automatically retries the vm creation in such a case). This PR implements a retry logic for the deletion and adds the relevant tests.

Below you can see a debug log of an example where the deletion is not retried, ultimately leading to the network interface becoming "abandoned" and therefore requiring manual intervention by an operator to delete the network interface and unblock the director.

D, [2025-11-27T04:10:37.572683 #747317] DEBUG -- [req_id cpi-875037]: [Aws::EC2::Client 200 0.092467 0 retries] describe_instances(instance_ids:["i-00296ecd9c9f26631"])

W, [2025-11-27T04:10:37.573357 #747317]  WARN -- [req_id cpi-875037]: Timed out waiting for instance 'i-00296ecd9c9f26631' to be running
W, [2025-11-27T04:10:37.573397 #747317]  WARN -- [req_id cpi-875037]: Failed to configure instance 'i-00296ecd9c9f26631': #<Bosh::Clouds::VMCreationFailed: Timed out waiting for instance 'i-00296ecd9c9f26631' to be running>
D, [2025-11-27T04:10:38.077263 #747317] DEBUG -- [req_id cpi-875037]: [Aws::EC2::Client 200 0.503579 0 retries] terminate_instances(instance_ids:["i-00296ecd9c9f26631"])

I, [2025-11-27T04:10:38.077371 #747317]  INFO -- [req_id cpi-875037]: Deleting instance settings for 'i-00296ecd9c9f26631'
I, [2025-11-27T04:10:38.077385 #747317]  INFO -- [req_id cpi-875037]: Deleting instance 'i-00296ecd9c9f26631'
D, [2025-11-27T04:10:38.147487 #747317] DEBUG -- [req_id cpi-875037]: [Aws::EC2::Client 200 0.069778 0 retries] describe_instances(instance_ids:["i-00296ecd9c9f26631"])

E, [2025-11-27T04:10:38.147926 #747317] ERROR -- [req_id cpi-875037]: Failed to terminate mis-configured instance 'i-00296ecd9c9f26631': #<Aws::Waiters::Errors::FailureStateError: stopped waiting, encountered a failure state>
I, [2025-11-27T04:10:38.147987 #747317]  INFO -- [req_id cpi-875037]: Deleting network_interface: eni-0eb14aebec9772cd0
D, [2025-11-27T04:10:38.403512 #747317] DEBUG -- [req_id cpi-875037]: [Aws::EC2::Client 400 0.255269 0 retries] delete_network_interface(network_interface_id:"eni-0eb14aebec9772cd0") Aws::EC2::Errors::InvalidParameterValue Network interface 'eni-0eb14aebec9772cd0' is currently in use.

W, [2025-11-27T04:10:38.403603 #747317]  WARN -- [req_id cpi-875037]: Network interface 'eni-0eb14aebec9772cd0' could not be deleted: Network interface 'eni-0eb14aebec9772cd0' is currently in use.
E, [2025-11-27T04:10:38.403642 #747317] ERROR -- [req_id cpi-875037]: Failed to create instance: Timed out waiting for instance 'i-00296ecd9c9f26631' to be running
/var/vcap/data/packages/bosh_aws_cpi/6350e37fd32ef512a6a32a35f1473fb5f0435ecc/lib/cloud/aws/instance.rb:69:in `rescue in wait_until_running'
/var/vcap/data/packages/bosh_aws_cpi/6350e37fd32ef512a6a32a35f1473fb5f0435ecc/lib/cloud/aws/instance.rb:59:in `wait_until_running'

[a-hassanin]

Thanks!