fix(profile-sync-controller): handle non-JSON error responses in authentication services

[mathieuartu]

Explanation

Related to: MetaMask/metamask-extension#37080

References

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them

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Note

Improves reliability of auth SDK by centralizing error handling and covering non‑JSON server errors.

• Add throwServiceError helper (with getResponseErrorMessage and isErrorResponse) to standardize HTTP/network error handling, including Retry-After parsing for 429
• Refactor getNonce, authenticate, authorizeOIDC, pairIdentifiers, and getUserProfileLineage to use the new helper and return domain-specific errors with consistent messages
• Add extensive tests for URLs, JSON/non-JSON error bodies, edge cases (null/undefined thrown values), and rate limiting
• Update CHANGELOG.md to document the change

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