telemetry_events: Rename AssistantEvent to AssistantEventData (#28133)

This PR renames the `AssistantEvent` type to `AssistantEventData`, as it
no longer represents the event itself, just the data needed to construct
it.

Pulling out of https://github.com/zed-industries/zed/pull/25179.

Release Notes:

- N/A

crates/client/src/telemetry.rs

@@ -17,7 +17,7 @@ use std::io::Write;
 use std::sync::LazyLock;
 use std::time::Instant;
 use std::{env, mem, path::PathBuf, sync::Arc, time::Duration};
-use telemetry_events::{AssistantEvent, AssistantPhase, Event, EventRequestBody, EventWrapper};
+use telemetry_events::{AssistantEventData, AssistantPhase, Event, EventRequestBody, EventWrapper};
 use util::{ResultExt, TryFutureExt};
 use worktree::{UpdatedEntriesSet, WorktreeId};
 
@@ -329,7 +329,7 @@ impl Telemetry {
         drop(state);
     }
 
-    pub fn report_assistant_event(self: &Arc<Self>, event: AssistantEvent) {
+    pub fn report_assistant_event(self: &Arc<Self>, event: AssistantEventData) {
         let event_type = match event.phase {
             AssistantPhase::Response => "Assistant Responded",
             AssistantPhase::Invoked => "Assistant Invoked",