Create Service Account: On Create check if two Service Accounts exist

[christiemolloy]

@jgiardino in the future is this something we would want to handle in the modal? Eg checking if two service accounts exist when the user hits the create button. Or even disabling the create service account button if two exist

[jgiardino]

We discussed this with @DuncanDoyle when reviewing the UX for the onboarding epic for Summit. In the control plane for MK, we are manually checking the current user against the list of Kafka instances to determine whether the Create Kafka instance button should be disabled because we knew we would not get an API call for this information, but we wanted a nicer experience for the Kafka instances page. He was fine with not doing this for service accounts.

It would be good to revisit this max-capacity flow post-summit.