Fix workspace migration failure (#36911)

This fixes a regression on nightly introduced in
https://github.com/zed-industries/zed/pull/36714

Release Notes:

- N/A

crates/workspace/src/path_list.rs

@@ -58,11 +58,7 @@ impl PathList {
         let mut paths: Vec<PathBuf> = if serialized.paths.is_empty() {
             Vec::new()
         } else {
-            serde_json::from_str::<Vec<PathBuf>>(&serialized.paths)
-                .unwrap_or(Vec::new())
-                .into_iter()
-                .map(|s| SanitizedPath::from(s).into())
-                .collect()
+            serialized.paths.split('\n').map(PathBuf::from).collect()
         };
 
         let mut order: Vec<usize> = serialized
@@ -85,7 +81,13 @@ impl PathList {
     pub fn serialize(&self) -> SerializedPathList {
         use std::fmt::Write as _;
 
-        let paths = serde_json::to_string(&self.paths).unwrap_or_default();
+        let mut paths = String::new();
+        for path in self.paths.iter() {
+            if !paths.is_empty() {
+                paths.push('\n');
+            }
+            paths.push_str(&path.to_string_lossy());
+        }
 
         let mut order = String::new();
         for ix in self.order.iter() {