add sync map to fix cocurrent write

[changluyi]

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What type of this PR

Examples of user facing changes:

• Features
• Bug fixes
• Docs
• Tests

Which issue(s) this PR fixes:

Fixes #2907

WHAT

🤖 Generated by Copilot at 67e9f20

This pull request enhances the pod deletion logic in the Controller type by using a sync.Map for the deletingPodObjMap field. This improves the thread-safety and performance of the controller when handling pod deletion events. The pull request modifies pkg/controller/controller.go and pkg/controller/pod.go to use the sync.Map type.

🤖 Generated by Copilot at 67e9f20

There once was a type called Controller
That managed the pods of a cluster
To delete them with care
It used a sync.Map there
And thus made its performance much bolder

HOW

🤖 Generated by Copilot at 67e9f20

• Replace regular map with sync.Map for deletingPodObjMap field of Controller type to improve thread-safety and avoid concurrent map access errors (link, link)
• Use Store method of sync.Map to atomically set the value for a key in deletingPodObjMap in various functions that enqueue pod events (link, link, link, link, link, link, link, link)
• Use Load method of sync.Map to atomically get the value for a key in deletingPodObjMap in functions that process pod deletion events (link, link)
• Use Delete method of sync.Map to atomically remove the value for a key in deletingPodObjMap in processNextDeletePodWorkItem function (link)
• Check the second return value of Load method to handle the case where the key is not found in deletingPodObjMap in handleDeletePod function (link)