Only generate copilot ThirdPartyNotices when publishing or releasing

[benvillalobos]

Quick win for https://vscodeteam.slack.com/archives/C1Y427SES/p1778478238390869

Gates the Generate NOTICE file step in build/azure-pipelines/product-copilot.yml so it only runs when VSCODE_PUBLISH or VSCODE_RELEASE is true, matching the conditional pattern used in product-quality-checks.yml.

No downstream step requires ThirdPartyNotices.txt:

• vsce package uses !ThirdPartyNotices.txt in .vscodeignore, which only un-ignores the file if present (no failure if absent).
• No other step in the pipeline reads it.

Side effect: copilot VSIXs produced by non-publishing CI runs will not contain ThirdPartyNotices.txt. Publishing/release builds are unchanged.

[Copilot]

Pull request overview

This PR narrows Copilot NOTICE generation in the product build pipeline so it is skipped for non-publishing CI runs.

Changes:

• Adds a runtime condition to the Copilot notice@0 step.
• Intended to run NOTICE generation only when publishing or releasing.

Show a summary per file

File	Description
build/azure-pipelines/product-copilot.yml	Adds a condition to the Generate NOTICE file task.

Copilot's findings

• Files reviewed: 1/1 changed files
• Comments generated: 1

[Copilot]

Copilot's findings

• Files reviewed: 2/2 changed files
• Comments generated: 0 new

[vs-code-engineering]

📬 CODENOTIFY

The following users are being notified based on files changed in this PR:

@lszomoru

Matched files:

• build/azure-pipelines/product-build.yml
• build/azure-pipelines/product-copilot.yml