Add pnpm installation to GitHub workflow files

[Copilot]

Description

PR #11139 migrates the codebase to use pnpm, but its workflow validation fails because the PR validation workflows run from main branch where pnpm isn't installed. This PR separates out the pnpm installation steps so they can be merged first.

Adds pnpm/action-setup@v4.2.0 with version 10 to workflows that need it:

• build.yaml - generate-bicep-types job
• lint.yaml - before TypeSpec/autorest installation
• functional-test-noncloud.yaml - before generate-bicep-types target
• codeql.yml - for JavaScript analysis (conditional on matrix.language == 'javascript')
• publish-docs.yaml - before TypeSpec installation
• validate-bicep.yaml - before Bicep validation

Type of change

• This pull request is a minor refactor, code cleanup, test improvement, or other maintenance task and doesn't change the functionality of Radius (issue link optional).

Contributor checklist

Please verify that the PR meets the following requirements, where applicable:

• An overview of proposed schema changes is included in a linked GitHub issue.
  • Yes
  • Not applicable
• A design document PR is created in the design-notes repository, if new APIs are being introduced.
  • Yes
  • Not applicable
• The design document has been reviewed and approved by Radius maintainers/approvers.
  • Yes
  • Not applicable
• A PR for the samples repository is created, if existing samples are affected by the changes in this PR.
  • Yes
  • Not applicable
• A PR for the documentation repository is created, if the changes in this PR affect the documentation or any user facing updates are made.
  • Yes
  • Not applicable
• A PR for the recipes repository is created, if existing recipes are affected by the changes in this PR.
  • Yes
  • Not applicable

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[radius-functional-tests]

Radius functional test overview

🔍 Go to test action run

Click here to see the test run details

Name	Value
Repository	radius-project/radius
Commit ref	b2aaf09
Unique ID	func62c1929c9f
Image tag	pr-func62c1929c9f

• gotestsum 1.13.0
• KinD: v0.29.0
• Dapr: 1.14.4
• Azure KeyVault CSI driver: 1.4.2
• Azure Workload identity webhook: 1.3.0
• Bicep recipe location ghcr.io/radius-project/dev/test/testrecipes/test-bicep-recipes/<name>:pr-func62c1929c9f
• Terraform recipe location http://tf-module-server.radius-test-tf-module-server.svc.cluster.local/<name>.zip (in cluster)
• applications-rp test image location: ghcr.io/radius-project/dev/applications-rp:pr-func62c1929c9f
• dynamic-rp test image location: ghcr.io/radius-project/dev/dynamic-rp:pr-func62c1929c9f
• controller test image location: ghcr.io/radius-project/dev/controller:pr-func62c1929c9f
• ucp test image location: ghcr.io/radius-project/dev/ucpd:pr-func62c1929c9f
• deployment-engine test image location: ghcr.io/radius-project/deployment-engine:latest

Test Status

⌛ Building Radius and pushing container images for functional tests...
✅ Container images build succeeded
⌛ Publishing Bicep Recipes for functional tests...
✅ Recipe publishing succeeded
⌛ Starting ucp-cloud functional tests...
⌛ Starting corerp-cloud functional tests...
✅ ucp-cloud functional tests succeeded
✅ corerp-cloud functional tests succeeded

[brooke-hamilton]

Closing in favor of a simpler solution to update the original PR with pnpm installation.