fix(core): deduplicate config reload namespace updates

[rootp1]

Purpose of PR?:

Summary

• deduplicate config-reload namespace updates so repeated endpoints in the same namespace do not replay the same posture and visibility work
• take an endpoint snapshot under EndPointsLock before iterating so the config-reload path reads a stable view of dm.EndPoints
• add focused tests for namespace deduplication and the concurrent snapshot pattern

Linked Issue

Fixes #2762

What Changed

• replaced per-endpoint config-reload updates with per-namespace updates derived from a deduplicated endpoint snapshot
• added uniqueEndpointNamespaces to centralize the namespace deduplication logic
• added focused unit and race-oriented coverage for the updated path

Verification

• make gofmt — passed
• go test ./... — failed: Darwin host hits existing Linux-specific build errors in common/utils (unix.Mount, unix.Sysinfo_t, unix.MemfdCreate)
• $(go env GOPATH)/bin/revive ./... — failed: repository has many pre-existing lint findings unrelated to this change
• $(go env GOPATH)/bin/gosec -exclude=G402,G115 ./... — failed: analysis is blocked by the same Darwin/Linux type errors, though it reported Issues: 0
• $(go env GOPATH)/bin/govulncheck ./... — failed: toolchain/package resolution requires Go 1.26 while the available toolchain tops out at the Go 1.25 compatibility layer used here
• cd tests && make — not run: the current upstream tree does not contain tests/Makefile

Scope

• only KubeArmor/core/unorchestratedUpdates.go and focused tests for that path were changed; unrelated files were not modified

Does this PR introduce a breaking change?

No.

If the changes in this PR are manually verified, list down the scenarios covered::

• Not manually verified in a Linux/Kubernetes runtime in this environment.

Additional information for reviewer? :

• This change stays within the config-reload path and intentionally avoids broader refactoring.

Checklist:

• Bug fix. Fixes Config reload replays namespace updates once per endpoint #2762
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• PR Title follows the convention of <type>(<scope>): <subject>
• Commit has unit tests
• Commit has integration tests