zlog: Replace usages of env_logger in tests with zlog (#31436)

Also fixes:
https://github.com/zed-industries/zed/pull/31400#issuecomment-2908165249

Release Notes:

- N/A *or* Added/Fixed/Improved ...

crates/collab/src/tests/debug_panel_tests.rs

@@ -18,9 +18,7 @@ use workspace::{Workspace, dock::Panel};
 use super::{TestClient, TestServer};
 
 pub fn init_test(cx: &mut gpui::TestAppContext) {
-    if std::env::var("RUST_LOG").is_ok() {
-        env_logger::try_init().ok();
-    }
+    zlog::init_test();
 
     cx.update(|cx| {
         theme::init(theme::LoadThemes::JustBase, cx);

crates/collab/src/tests/integration_tests.rs

@@ -56,9 +56,7 @@ use workspace::Pane;
 
 #[ctor::ctor]
 fn init_logger() {
-    if std::env::var("RUST_LOG").is_ok() {
-        env_logger::init();
-    }
+    zlog::init_test();
 }
 
 #[gpui::test(iterations = 10)]

crates/collab/src/tests/remote_editing_collaboration_tests.rs

@@ -589,9 +589,7 @@ async fn test_remote_server_debugger(
     cx_a.update(|cx| {
         release_channel::init(SemanticVersion::default(), cx);
         command_palette_hooks::init(cx);
-        if std::env::var("RUST_LOG").is_ok() {
-            env_logger::try_init().ok();
-        }
+        zlog::init_test();
         dap_adapters::init(cx);
     });
     server_cx.update(|cx| {