feat: Send telemetry event when suggestion stream is accepted

Description

It adds the functionality to send the telemetry event to the LS when the suggestion stream is accepted.

References gitlab-org/editor-extensions/gitlab-lsp#150 (closed) and should be tested together with this MR gitlab-org/editor-extensions/gitlab-lsp!237 (merged).

• follow these instructions to setup the local snowplow collector
• link the LS bundle from gitlab-org/editor-extensions/gitlab-lsp!237 (merged) to the extension built from this branch
• Trigger some generation (streamed suggestion) and accept it.
• Make sure that the suggestion_accepted event is tracked. The following events should be tracked when the suggestion was accepted requested => stream_stared => shown => (stream_completed only if accepted full stream) => accepted