Fix misleading message for launch lifecycle events logged as drain operations

[baburciu]

Issue #, if available:

Description of changes:

This fix resolves a message confusion where launch lifecycle events were misleadingly logged as "drain" operations when they're actually doing the opposite.

• Updated logging interface: renamed RequestingInstanceDrain() to ProcessingInterruptionEvent()
• Added event-type awareness: the logging function now uses a switch statement based on event.Kind

Before the fix: Everything logged "Requesting instance drain"

{
    "level": "info",
    "event": {
        "EventID": "asg-lifecycle-term-65343736363839362d346666352d303536352d656661622d303432326331343631666665",
        "Kind": "ASG_LAUNCH_LIFECYCLE",
        "Monitor": "SQS_MONITOR",
        "Description": "ASG Lifecycle Launch event received. Instance was started at 2025-10-27 12:10:53.217 +0000 UTC \n",
        "State": "",
        "AutoScalingGroupName": "on-demand-huge-workers-01-2024112121084029580000002c",
        "NodeName": "ip-10-31-16-222.eu-west-1.compute.internal",
        "NodeLabels": null,
        "Pods": null,
        "InstanceID": "i-070c03698c54561a9",
        "ProviderID": "aws:///eu-west-1a/i-070c03698c54561a9",
        "InstanceType": "",
        "IsManaged": true,
        "StartTime": "2025-10-27T12:10:53.217Z",
        "EndTime": "0001-01-01T00:00:00Z",
        "NodeProcessed": false,
        "InProgress": false
    },
    "time": "2025-10-27T12:11:16Z",
    "message": "Adding new event to the event store"
}
{
    "level": "info",
    "event-id": "asg-lifecycle-term-65343736363839362d346666352d303536352d656661622d303432326331343631666665",
    "kind": "ASG_LAUNCH_LIFECYCLE",
    "node-name": "ip-10-31-16-222.eu-west-1.compute.internal",
    "instance-id": "i-070c03698c54561a9",
    "provider-id": "aws:///eu-west-1a/i-070c03698c54561a9",
    "time": "2025-10-27T12:11:17Z",
    "message": "Requesting instance drain"  #<==
}

After the fix:

• Only launch lifecycle events get the specific message "Waiting for node to be ready before completing ASG launch lifecycle"
• Everything else (including actual drain operations) still gets "Requesting instance drain"

{
    "level": "info",
    "event": {
        "EventID": "asg-lifecycle-term-32346536363839392d326162342d376165612d323936332d376438383166333631323932",
        "Kind": "ASG_LAUNCH_LIFECYCLE",
        "Monitor": "SQS_MONITOR",
        "Description": "ASG Lifecycle Launch event received. Instance was started at 2025-10-27 15:30:25.519 +0000 UTC \n",
        "State": "",
        "AutoScalingGroupName": "on-demand-huge-workers-01-2024112121084029580000002c",
        "NodeName": "ip-10-31-26-73.eu-west-1.compute.internal",
        "NodeLabels": null,
        "Pods": null,
        "InstanceID": "i-069246571a8ee057a",
        "ProviderID": "aws:///eu-west-1c/i-069246571a8ee057a",
        "InstanceType": "",
        "IsManaged": true,
        "StartTime": "2025-10-27T15:30:25.519Z",
        "EndTime": "0001-01-01T00:00:00Z",
        "NodeProcessed": false,
        "InProgress": false
    },
    "time": "2025-10-27T15:30:25Z",
    "message": "Adding new event to the event store"
}
{
    "level": "info",
    "event-id": "asg-lifecycle-term-32346536363839392d326162342d376165612d323936332d376438383166333631323932",
    "kind": "ASG_LAUNCH_LIFECYCLE",
    "node-name": "ip-10-31-26-73.eu-west-1.compute.internal",
    "instance-id": "i-069246571a8ee057a",
    "provider-id": "aws:///eu-west-1c/i-069246571a8ee057a",
    "time": "2025-10-27T15:30:26Z",
    "message": "Waiting for node to be ready before completing ASG launch lifecycle"  #<==
}

How you tested your changes:
Environment (Linux / Windows): Linux
Kubernetes Version: v1.31.13

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.