Web: Add auto discover capability to EC2 enrollment

[kimlisa]

resolves #35435

• e2e tested on my staging cluster (see demo)
• DiscoveryService: prevent EICE Node duplication #40220

New additions related to auto discover:

• add discover toggler
  • self-hosted gets instructions on how to add one by themselves
  • cloud has a discovery service already running so just the toggler is required
• when ready to enroll (click next), we gather all the required vpc and its subnets and than query for existing ec2 instsance connection endpoint with the vpc filter
  • if the queried results == to the vpc filter we sent it, that means all the endpoints has already been deployed (skips the deployment step, goes straight to set up access screen)
    • we poll only if the queried endpoints status is create-in-progress and poll until create-complete
  • if queried results != to the vpc filter we sent it, that means we need to deploy some endpoints (takes user to deployment step)
    • we poll until all the endpoints we deployed comes back as create-complete status

Demo
https://www.loom.com/share/4b5a6ac44c53452a9c05c946cc69ba0c

changelog: Add auto discover capability to EC2 enrollment in the web UI

[avatus]

what would make this resp null or undefined?

[kimlisa]

it's not guaranteed that the backend will return an empty array, as an empty array, it can come back as null/undefined

i think it's when you define something like this:

var someSlice []string

if this gets sent as is, it's undefined. i don't remember where but it bit us before, so anytime i expect an array, i just check for undefined/null

[kimlisa]

@rudream @avatus ok i finished writing tests, PTAL! 🙏

[avatus]

Suggested change

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[public-teleport-github-review-bot]

@kimlisa See the table below for backport results.

Branch	Result
branch/v15	Failed