Add tests for multiple sync tokens scenarios

[linglingye001]

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[Copilot]

Pull request overview

Adds support for sync token response headers that contain whitespace after commas (which can occur when HTTP intermediaries join duplicate sync-token headers), and adds tests covering multi-token scenarios.

Changes:

• Trim each comma-separated segment before parsing in SyncTokens.addSyncTokenFromHeaderValue so values like "a=v;sn=1, b=v;sn=2" parse correctly.
• Add unit tests for multiple sync tokens in a single header and for tokens with spaces after commas.

Reviewed changes

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

File	Description
sdk/appconfiguration/app-configuration/src/internal/syncTokenPolicy.ts	Trim each token segment after splitting on , before parsing.
sdk/appconfiguration/app-configuration/test/internal/node/http.spec.ts	New tests for multi-token responses and space-after-comma joined headers.