Add managed identity configuration instructions for Cosmos DB connector (#316060) * Add managed identity configuration instructions for Cosmos DB connector * Add screenshot for user-assigned managed identity connection configuration * Convert screenshot from JPEG to actual PNG format * Fix image path to use relative ./ prefix * Match image tag style with existing images (no ./ prefix, consistent formatting) * Update articles/connectors/connectors-create-api-cosmos-db.md Co-authored-by: Esther Fan <ecfan@users.noreply.github.com> * Apply suggestions from code review Co-authored-by: Esther Fan <ecfan@users.noreply.github.com> * Fix screenshot: replace blurred sensitive info with solid color block and placeholder text * Fix screenshot: correct subscription-ID casing, preserve field border * Fix squished Cosmos DB icon: replace with properly proportioned square icon * Fix cut-off W: replace header row using properly proportioned reference * Fix textarea border: restore right border on Managed Identity field --------- Co-authored-by: TheovanKraay <TheovanKraay@users.noreply.github.com> Co-authored-by: Esther Fan <ecfan@users.noreply.github.com>