debugger: Remove fake adapter and un-gate GDB (#27557)

This is a clean-up PR in anticipation of introduction of Debugger
Registry. I wanna get rid of DebugAdapterKind (or rather, it being an
enum).
Release Notes:

- N/A

---------

Co-authored-by: Anthony Eid <hello@anthonyeid.me>
Co-authored-by: Anthony <anthony@zed.dev>

crates/debugger_ui/src/tests/module_list.rs

@@ -5,7 +5,7 @@ use crate::{
 };
 use dap::{
     requests::{Modules, StackTrace, Threads},
-    DebugRequestType, StoppedEvent,
+    StoppedEvent,
 };
 use gpui::{BackgroundExecutor, TestAppContext, VisualTestContext};
 use project::{FakeFs, Project};
@@ -13,6 +13,7 @@ use std::sync::{
     atomic::{AtomicBool, AtomicI32, Ordering},
     Arc,
 };
+use task::LaunchConfig;
 
 #[gpui::test]
 async fn test_module_list(executor: BackgroundExecutor, cx: &mut TestAppContext) {
@@ -30,15 +31,13 @@ async fn test_module_list(executor: BackgroundExecutor, cx: &mut TestAppContext)
     let cx = &mut VisualTestContext::from_window(*workspace, cx);
 
     let task = project.update(cx, |project, cx| {
-        project.start_debug_session(
-            dap::test_config(
-                DebugRequestType::Launch,
-                None,
-                Some(dap::Capabilities {
-                    supports_modules_request: Some(true),
-                    ..Default::default()
-                }),
-            ),
+        project.fake_debug_session(
+            dap::DebugRequestType::Launch(LaunchConfig::default()),
+            Some(dap::Capabilities {
+                supports_modules_request: Some(true),
+                ..Default::default()
+            }),
+            false,
             cx,
         )
     });