Retina pod crashes when nil ip is passed to enricher

[LakshK98]

The enricher code does not check if the ip pointer passed to it is null before dereferencing it which can cause the pod to crash with the following error.

ts=2025-10-06T18:54:25.884Z level=error caller=enricher/enricher.go:110 msg="IP version is not supported" IPVersion=IPv6
ts=2025-10-06T18:54:25.884Z level=error caller=enricher/enricher.go:110 msg="IP version is not supported" IPVersion=IPv6
panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xc0000005 code=0x0 addr=0x38 pc=0x1ed7e3e]

goroutine 47 [running]:
github.com/microsoft/retina/pkg/enricher.(*Enricher).enrich(0xc0009053c0, 0x27ff9fa?)
        /go/src/github.com/microsoft/retina/pkg/enricher/enricher.go:109 +0x3e
github.com/microsoft/retina/pkg/enricher.(*Enricher).Run.func1()
        /go/src/github.com/microsoft/retina/pkg/enricher/enricher.go:89 +0x1dc
created by github.com/microsoft/retina/pkg/enricher.(*Enricher).Run in goroutine 1
        /go/src/github.com/microsoft/retina/pkg/enricher/enricher.go:69 +0x4f