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/task/Cargo.toml

@@ -17,11 +17,11 @@ workspace = true
 [dependencies]
 anyhow.workspace = true
 collections.workspace = true
-dap-types.workspace = true
 futures.workspace = true
 gpui.workspace = true
 hex.workspace = true
 parking_lot.workspace = true
+proto.workspace = true
 schemars.workspace = true
 serde.workspace = true
 serde_json.workspace = true