debugger: More tidy up for SSH (#28993)

Split `locator` out of DebugTaskDefinition to make it clearer when
location needs to happen.

Release Notes:

- N/A

---------

Co-authored-by: Anthony Eid <hello@anthonyeid.me>
Co-authored-by: Anthony <anthony@zed.dev>
Co-authored-by: Cole Miller <m@cole-miller.net>

crates/proto/src/proto.rs

@@ -302,6 +302,10 @@ messages!(
     (GitDiff, Background),
     (GitDiffResponse, Background),
     (GitInit, Background),
+    (GetDebugAdapterBinary, Background),
+    (DebugAdapterBinary, Background),
+    (RunDebugLocator, Background),
+    (DebugTaskDefinition, Background),
 );
 
 request_messages!(
@@ -460,6 +464,8 @@ request_messages!(
     (GitDiff, GitDiffResponse),
     (GitInit, Ack),
     (ToggleBreakpoint, Ack),
+    (GetDebugAdapterBinary, DebugAdapterBinary),
+    (RunDebugLocator, DebugTaskDefinition),
 );
 
 entity_messages!(
@@ -579,6 +585,8 @@ entity_messages!(
     GitInit,
     BreakpointsForFile,
     ToggleBreakpoint,
+    RunDebugLocator,
+    GetDebugAdapterBinary,
 );
 
 entity_messages!(