Add instance name to DiscoverEC2 User Task failed instances list

[marcoandredinis]

This PR adds the Instance Name to the DiscoverEC2 UserTasks.
This adds an extra information that will help the user identify what instances the issue is referring to.

Previously, only the instance id was present.

Demo:

kind: user_task
metadata:
  expires:
    nanos: 798511000
    seconds: 1729265153
  name: 79298717-1cd0-57a8-9977-5cbdc3446b31
  revision: 1a96be07-d30f-40ff-9e08-d876ca273b2e
spec:
  discover_ec2:
    account_id: "123456789012"
    instances:
      i-123:
        discovery_config: dc001
        discovery_group: aws-prod
        instance_id: i-123
        name: MarcoTasksSSMConnectionLost
        sync_time:
          nanos: 630000000
          seconds: 1729264793
    region: eu-west-2
  integration: teleportdev
  issue_type: ec2-ssm-agent-connection-lost
  state: OPEN
  task_type: discover-ec2
version: v1
---
kind: user_task
metadata:
  expires:
    nanos: 266377000
    seconds: 1729265153
  name: a6a22f27-60d7-5b80-b309-3540b199f00e
  revision: a4e7b5a6-bbfd-45be-b810-9303acebf218
spec:
  discover_ec2:
    account_id: "123456789012"
    instances:
      i-123:
        discovery_config: dc001
        discovery_group: aws-prod
        instance_id: i-123
        name: MarcoTasksSSMNotRegistered02
        sync_time:
          nanos: 810000000
          seconds: 1729264792
      i-123:
        discovery_config: dc001
        discovery_group: aws-prod
        instance_id: i-123
        name: MarcoTasksSSMNotRegistered
        sync_time:
          nanos: 102000000
          seconds: 1729264793
    region: eu-west-2
  integration: teleportdev
  issue_type: ec2-ssm-agent-not-registered
  state: OPEN
  task_type: discover-ec2
version: v1
---
kind: user_task
metadata:
  expires:
    nanos: 532998000
    seconds: 1729265153
  name: f07cd290-1893-579e-9126-327529fd364e
  revision: 2271fdf5-79a4-4139-9b36-285d1be0a1f1
spec:
  discover_ec2:
    account_id: "123456789012"
    instances:
      i-123:
        discovery_config: dc001
        discovery_group: aws-prod
        instance_id: i-123
        name: MarcoTasksSSMUnsupportedOS
        sync_time:
          nanos: 364000000
          seconds: 1729264793
    region: eu-west-2
  integration: teleportdev
  issue_type: ec2-ssm-unsupported-os
  state: OPEN
  task_type: discover-ec2
version: v1