bundle: filter VSCode server chatter

[MikeMcQuaid]

• ignore VSCode server progress output during extension dumps
• keep only extension-shaped identifiers in Brewfile output

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[Copilot]

Pull request overview

This PR improves brew bundle dump --vscode resilience by filtering out non-extension “chatter” that can appear in code --list-extensions output (e.g., VSCode server setup/progress lines), ensuring Brewfile output contains only valid extension identifiers.

Changes:

• Add an EXTENSION_ID_REGEX and filter --list-extensions output to keep only extension-shaped IDs (after stripping whitespace).
• Add an RSpec case covering VSCode server setup/progress output mixed into the extension list.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
Library/Homebrew/bundle/extensions/vscode_extension.rb	Filters code --list-extensions output to only retain valid extension identifiers, reducing noisy/non-extension lines in dumps.
Library/Homebrew/test/bundle/vscode_extension_spec.rb	Adds test coverage ensuring server/progress output is ignored and only real extension IDs are returned.

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