The SDK should have an option sendDefaultPii and when any event goes through, that doesn't have ip_address set, the SDK should set it to {{auto}} to instruct the server to use the connection IP address as the user address.

Add to: https://github.com/getsentry/sentry-docs/blob/9887bd548e8acc4ffa6454b141b8ba8cb8f7a79d/src/platforms/common/configuration/options.mdx#L88.
PR for updating the docs: getsentry/sentry-docs#2983