update Workload Identity doc for ASO

[nojnhuh]

What type of PR is this?
/kind documentation

What this PR does / why we need it:

Authenticating with WorkloadIdentity requires federated credentials for both the CAPZ ServiceAccount and the ASO ServiceAccount. This PR updates the docs to reflect that.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Related to #3851, #3770

Special notes for your reviewer:

• cherry-pick candidate

TODOs:

• squashed commits
• includes documentation
• adds unit tests

Release note:

NONE

[nojnhuh]

/cherry-pick release-1.11

[k8s-infra-cherrypick-robot]

@nojnhuh: once the present PR merges, I will cherry-pick it on top of release-1.11 in a new PR and assign it to you.

In response to this:

/cherry-pick release-1.11

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (2e333aa) 56.58% compared to head (d664747) 56.58%.
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4017   +/-   ##
=======================================
  Coverage   56.58%   56.58%           
=======================================
  Files         187      187           
  Lines       19126    19126           
=======================================
  Hits        10823    10823           
  Misses       7672     7672           
  Partials      631      631           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[CecileRobertMichon]

lgtm

should we cherry-pick this to 1.11 so it's in the book? looks like you already did

/assign @sonasingh46

[CecileRobertMichon]

/lgtm
/approve

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 215434179c3f1037b49dbaf0bb30157d92393390

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: CecileRobertMichon

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• OWNERS [CecileRobertMichon]

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[k8s-infra-cherrypick-robot]

@nojnhuh: new pull request created: #4024

In response to this:

/cherry-pick release-1.11

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.