fix(service): omit nil endpoints and prefer endpointsForHostname()

[yurrriq]

Description

From Services, don't try to create records for invalid endpoints, e.g. when they contain a label that's too long (ref: #3017)

Add a test to make sure Ingresses behave as expected, too.

Checklist

• Unit tests updated
• End user documentation updated

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[k8s-ci-robot]

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[yurrriq]

I wanted to open this early and see if there's buy-in... see also: https://kubernetes.slack.com/archives/C771MKDKQ/p1709242006124009

[szuecs]

/ok-to-test

[szuecs]

@yurrriq there is a linter that claims "unused const":

 golangci-lint run --timeout=30m ./...
Error: source/service.go:40:2: const `defaultTargetsCapacity` is unused (unused)
	defaultTargetsCapacity = 10

[yurrriq]

@yurrriq there is a linter that claims "unused const":

 golangci-lint run --timeout=30m ./...
Error: source/service.go:40:2: const `defaultTargetsCapacity` is unused (unused)
	defaultTargetsCapacity = 10

Yep, good catch. Since switching to endpointsForHostname we don't use/need it anymore

[szuecs]

/approve
/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: szuecs

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