Describe the single 429 retry correctly in two adapters - #1651

Summary

Follow-up to #1648. Two adapters told the model that the connector retries a 429 automatically with (exponential) backoff. The REST engine retries a 429 exactly once (retryDelayMs in rest.engine.ts: after Retry-After when it is at most 3 s, after about a second when there is none, not at all when it is longer), so the model may wrongly assume a throttled call was retried several times.

Changes

• intl/amazon-seller.json: the rate-limit sentence now describes the single retry and asks to wait before calling again.
• intl/google-analytics-4.json: same for the 429 line under quotas.
• Other adapters that say "429 → exponential backoff" (Nimble, OpenWeather, Zoho CRM) only advise the model what to do and are left as they are.

Type

• Bug fix

Testing

• No tests needed (instruction text only)
• From the repo root: node scripts/regenerate-catalog.mjs → no diff (catalog.ts carries no instruction text); node scripts/validate-adapters.mjs --warn → exit 0, output identical to the same run without the change (no new warnings).

Checklist

• My code follows the existing code style
• This PR has a descriptive title

Related Issues

Follow-up to #1648.