Add telemetry for supermaven (#11821)

Data migration plan:

- [X] Make a duplicate table of `copilot_events`
    - Name: `inline_completion_events`
    - Omit `suggestion_id` column
- [X-reverted-skipping] In collab, continue to match on copilot_events,
but simply stuff their data into inline_completion_events, to forward it
to the new table
- [skipping] Once collab is deployed, ensure no events are being sent to
copilot_events, migrate `copilot_events` to new table via a transaction
- [skipping] Delete `copilot_events` table

---

- [X] Locally test that copilot events sent from old clients get put
into inline_completions_table
- [X] Locally test that copilot events and supermaven events sent from
new clients get put into inline_completions_table

---

- [X] Why are discard events being spammed?
- A:
8d4315712b/crates/editor/src/editor.rs (L2147)


![scr-20240514-pqmg](https://github.com/zed-industries/zed/assets/19867440/e51e7ae4-21b8-47a2-bfaa-f68fb355e409)

This will throw off the past results for accepted / dismissed that I was
wanting to use to evaluate Supermaven quality, by comparing its rate
with copilot's rate.

I'm not super thrilled with this fix, but I think it'll do. In the
`supermaven_completions_provider`, we check if there's a `completion_id`
before sending either an accepted or discard completion event. I don't
see a similar construct in the `copilot_completions_provider` to
piggyback off of, so I begrudgingly introduced
`should_allow_event_to_send` and had it follow the same pattern that
`completion_id` does. Maybe there's a better way?

---

Adds events to supermaven suggestions. Makes "CopilotEvents" generic ->
"InlineCompletionEvents".

Release Notes:

- N/A

crates/telemetry_events/src/telemetry_events.rs

@@ -53,7 +53,8 @@ impl Display for AssistantKind {
 #[serde(tag = "type")]
 pub enum Event {
     Editor(EditorEvent),
-    Copilot(CopilotEvent),
+    Copilot(CopilotEvent), // Needed for clients sending old copilot_event types
+    InlineCompletion(InlineCompletionEvent),
     Call(CallEvent),
     Assistant(AssistantEvent),
     Cpu(CpuEvent),
@@ -74,6 +75,7 @@ pub struct EditorEvent {
     pub copilot_enabled_for_language: bool,
 }
 
+// Needed for clients sending old copilot_event types
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 pub struct CopilotEvent {
     pub suggestion_id: Option<String>,
@@ -81,6 +83,13 @@ pub struct CopilotEvent {
     pub file_extension: Option<String>,
 }
 
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+pub struct InlineCompletionEvent {
+    pub provider: String,
+    pub suggestion_accepted: bool,
+    pub file_extension: Option<String>,
+}
+
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 pub struct CallEvent {
     pub operation: String,