Outbound webhook event for LinkedIn connection requests (sent/accepted)

Add a webhook event category for LinkedIn connection actions in the Sequencer, so customers can route this data to external tools (CRMs like GoHighLevel, Zapier/Make, etc.) the same way page/sheet events already work. Requested events: - connection_request:sent — fires when a Send Connection step sends a request to a contact - connection_request:accepted / connection_request:declined — fires on the existing internal Unipile-backed acceptance signal (already used internally to advance sequences, but not currently exposed as a subscribable outbound event) Customer context: a user wanted to push "people I sent a LinkedIn connection request to" from Sendr into GoHighLevel via a webhook, to trigger their own GHL automation. Today this isn't possible — Sendr's outbound webhook catalogue only covers page render, page engagement, template, and sheet events (see Webhook Events Reference). The connection-accept/decline signal exists internally (Send Connection step listens for a Unipile webhook to advance the sequence) but is not exposed externally. Related existing requests: "Subscribe to reply notifications via webhooks" and "Wait for connection acceptance in sequences, with automatic accepted/not-accepted branching" reflect the same underlying gap (LinkedIn/sequence events not exposed as webhooks).