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/project/src/git_store/conflict_set.rs

@@ -463,7 +463,7 @@ mod tests {
 
     #[gpui::test]
     async fn test_conflict_updates(executor: BackgroundExecutor, cx: &mut TestAppContext) {
-        env_logger::try_init().ok();
+        zlog::init_test();
         cx.update(|cx| {
             settings::init(cx);
             WorktreeSettings::register(cx);

crates/project/src/git_store/git_traversal.rs

@@ -674,9 +674,7 @@ mod tests {
     }
 
     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| {
             let settings_store = SettingsStore::test(cx);

crates/project/src/image_store.rs

@@ -739,9 +739,7 @@ mod tests {
     use std::path::PathBuf;
 
     pub fn init_test(cx: &mut TestAppContext) {
-        if std::env::var("RUST_LOG").is_ok() {
-            env_logger::try_init().ok();
-        }
+        zlog::init_test();
 
         cx.update(|cx| {
             let settings_store = SettingsStore::test(cx);

crates/project/src/project_tests.rs

@@ -8528,9 +8528,7 @@ async fn search(
 }
 
 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| {
         let settings_store = SettingsStore::test(cx);

crates/project/src/task_inventory.rs

@@ -1191,9 +1191,7 @@ mod tests {
     }
 
     fn init_test(_cx: &mut TestAppContext) {
-        if std::env::var("RUST_LOG").is_ok() {
-            env_logger::try_init().ok();
-        }
+        zlog::init_test();
         TaskStore::init(None);
     }