Send repoInfo telemetry for each repo in multi-repo workspaces

[vijayupadya]

The repoInfo telemetry event was previously emitted only for the active repository on each chat request. In multi-repo workspaces (and especially long-tail cases like git.autoRepositoryDetection: 'subFolders' with many submodules), this dropped visibility into all the other repos in scope. This PR extends RepoInfoTelemetry to emit one event per repository, while bounding cost and preserving all existing behavior for single-repo workspaces.

[Copilot]

Pull request overview

This PR updates the Copilot extension’s RepoInfoTelemetry so that, in multi-repo workspaces, it emits request.repoInfo telemetry once per repository (bounded to a small cap) instead of only for the active repository. This improves visibility for scenarios like git.autoRepositoryDetection: 'subFolders' with many repos/submodules while keeping single-repo behavior intact.

Changes:

• Emit repoInfo telemetry per repository (with repoIndex, repoCount, and isActiveRepository) and cap processing to 5 repos per request while always including the active repo.
• Scope filesystem watchers to the repo root so changes in sibling repos don’t invalidate diff results.
• Add test coverage for multi-repo emission, capping behavior, and per-repo end-event gating.

Show a summary per file

File	Description
extensions/copilot/src/extension/prompt/node/repoInfoTelemetry.ts	Refactors repoInfo telemetry to iterate over repositories (capped), adds repo indexing/active markers, and scopes file watching per repo.
extensions/copilot/src/extension/prompt/node/test/repoInfoTelemetry.spec.ts	Adds multi-repo unit tests and adjusts git service mocking to support repo list semantics.

Copilot's findings

• Files reviewed: 2/2 changed files
• Comments generated: 1