Update Microsoft Sitelink

EDITS an existing Microsoft (Bing) sitelink extension in place — its link text, final URL or description lines — keeping its id, campaign associations and history (no delete and recreate). Only the fields you pass change; empty text/final_url = unchanged. description1/description2 are set together (≤35 chars each); pass both as '' to remove the descriptions. Text may contain '|'. The sitelink is one object in the account library, so the change shows on EVERY campaign it is attached to (see campaign_ids in list_microsoft_ad_extensions, where extension_id also comes from). The edited sitelink goes through Microsoft editorial review again. confirm=false = preview, confirm=true applies.