[release/10.0] Move Linux CI jobs off Microsoft-hosted pools (backport #64842, #65867)

[mmitche]

Summary

Backport of #64842 and #65867 to release/10.0.

release/10.0 predates these PRs, so its default-build.yml still uses the old
useHostedUbuntu: true default, which routes Linux CI/PR jobs to the
Microsoft-hosted vmImage: ubuntu-22.04 pool. This includes the queue-bound
Components E2E ("Test: Blazor E2E tests on Linux") job and the Linux cross-build
legs, which incur multi-hour agent-queue waits on the finite hosted pool.

This change brings release/10.0 in line with main: it renames the parameter
to use1ESUbuntu (default false) and routes Linux jobs to the .NET-owned
dnceng pool ($(DncEngPublicBuildPool) / $(DncEngInternalBuildPool)) with the
1es-ubuntu-2204(-open) or Build.Ubuntu.2204.Amd64(.Open) images.

Backported PRs

• Switch default for useHostedUbuntu to false and use dnceng pool #64842 — Switch default for useHostedUbuntu to false and use dnceng pool
• Fix Ubuntu build image #65867 — Fix Ubuntu build image (Build.Ubuntu.2204 → Build.Ubuntu.2204.Amd64)

Changes

File	Change
jobs/default-build.yml	Rename useHostedUbuntu (default true) → use1ESUbuntu (default false); route public/internal Linux to the dnceng pool with 1es-ubuntu-2204(-open) (when use1ESUbuntu: true) or Build.Ubuntu.2204.Amd64(.Open) (else)
jobs/components-e2e-test-job.yml	Set use1ESUbuntu: true (Blazor E2E)
ci.yml, ci-public.yml, ci-unofficial.yml	Remove useHostedUbuntu: false; add use1ESUbuntu: true to Linux ARM + ARM64
quarantined-pr.yml	Remove useHostedUbuntu: false

Notes

• The change was applied semantically (not a literal cherry-pick) because
  release/10.0 has diverged from the PRs' base (the Components E2E job is split
  into jobs/components-e2e-test-job.yml, and the Linux cross legs are structured
  differently). The resulting pool logic matches main.
• release/10.0's Windows images (windows.vs2022.amd64[.open]) are intentionally
  left unchanged — the Windows image bump on main was a separate PR, not part of
  Switch default for useHostedUbuntu to false and use dnceng pool #64842/Fix Ubuntu build image #65867.
• After the parameter rename, any lingering useHostedUbuntu reference would be an
  undeclared-parameter error, so every pipeline that passed it was updated. Verified
  no useHostedUbuntu remains and all changed YAML files parse.

Relates to dnceng AB#11633.

[dotnet-policy-service]

Hey @dotnet/aspnet-build, looks like this PR is something you want to take a look at.

[Copilot]

Pull request overview

Backport to release/10.0 that moves Linux CI jobs off the Microsoft-hosted ubuntu-22.04 pool and onto the .NET-owned dnceng pools/images, aligning the branch’s pipeline behavior with main (per backports of #64842 and #65867).

Changes:

• Rename pipeline parameter useHostedUbuntu → use1ESUbuntu (default false) and update Linux pool selection logic in the shared default-build.yml job template.
• Route public/internal Linux jobs to dnceng pools using 1es-ubuntu-2204(-open) when use1ESUbuntu: true, otherwise Build.Ubuntu.2204.Amd64(.Open).
• Update CI entry pipelines and the Components E2E job to remove the old parameter and enable use1ESUbuntu: true where intended (E2E + Linux ARM/ARM64 legs).

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
.azure/pipelines/quarantined-pr.yml	Drops the old useHostedUbuntu override so the job follows the updated default-build template’s defaults.
.azure/pipelines/jobs/default-build.yml	Implements use1ESUbuntu and updates Linux pool/image selection for public + internal templates.
.azure/pipelines/jobs/components-e2e-test-job.yml	Enables use1ESUbuntu: true for the Blazor E2E Linux job.
.azure/pipelines/ci.yml	Removes useHostedUbuntu usage and enables use1ESUbuntu for Linux ARM/ARM64 legs.
.azure/pipelines/ci-unofficial.yml	Same parameter cleanup + use1ESUbuntu enablement for Linux ARM/ARM64 legs.
.azure/pipelines/ci-public.yml	Same parameter cleanup + use1ESUbuntu enablement for Linux ARM/ARM64 legs.

[mmitche]

@wtgodbe Some aspnetcore servicing PRs are showing up in the "extra slow" bucket, due to waiting on hosted pool machines. This should reduce the pressure on those pools somewhat.