Enhance DLQ CloudEvents with destination

[travis-minke-sap]

Fixes #5726

Proposed Changes

• 🎁 Enhance DLQ CloudEvents with destination or reply URL in new knativeerrordest extension attribute.

Pre-review Checklist

• At least 80% unit test coverage
• E2E tests for any new behavior (N/A)
• Docs PR for any user-facing impact
• Spec PR for any new API feature. (N/A)
• Conformance test for any change to the spec (N/A)

Release Note

Dead Letter Sink CloudEvents from certain Channels will include the "ce-knativeerrordest" extension attribute indicating the original destination URL of the failed event.

Docs

See documentation PR #4228

[knative-prow-robot]

Hi @travis-minke-sap. Thanks for your PR.

I'm waiting for a knative member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[codecov]

Codecov Report

Merging #5727 (fa606a4) into main (7266621) will increase coverage by 0.01%.
The diff coverage is 75.00%.

@@            Coverage Diff             @@
##             main    #5727      +/-   ##
==========================================
+ Coverage   82.68%   82.69%   +0.01%     
==========================================
  Files         200      200              
  Lines        6261     6265       +4     
==========================================
+ Hits         5177     5181       +4     
  Misses        750      750              
  Partials      334      334              

Impacted Files	Coverage Δ
pkg/channel/message_dispatcher.go	79.03% <66.66%> (+0.51%)	⬆️
pkg/channel/attributes/knative_error.go	100.00% <100.00%> (ø)

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[lionelvillard]

/ok-to-test

Can you also add this new extension to the doc: https://knative.dev/docs/developer/eventing/event-delivery/? Already done

[matzew]

/lgtm

[knative-metrics-robot]

The following is the coverage report on the affected files.
Say /test pull-knative-eventing-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/channel/message_dispatcher.go	86.6%	87.0%	0.3

[matzew]

/lgtm
/approve

[knative-prow-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: matzew, travis-minke-sap

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