context_server: Change command string field to PathBuf (#34873)

Release Notes:

- N/A

crates/agent_ui/src/agent_configuration/configure_context_server_modal.rs

@@ -1,4 +1,5 @@
 use std::{
+    path::PathBuf,
     sync::{Arc, Mutex},
     time::Duration,
 };
@@ -188,7 +189,7 @@ fn context_server_input(existing: Option<(ContextServerId, ContextServerCommand)
         }
         None => (
             "some-mcp-server".to_string(),
-            "".to_string(),
+            PathBuf::new(),
             "[]".to_string(),
             "{}".to_string(),
         ),
@@ -199,13 +200,14 @@ fn context_server_input(existing: Option<(ContextServerId, ContextServerCommand)
   /// The name of your MCP server
   "{name}": {{
     /// The command which runs the MCP server
-    "command": "{command}",
+    "command": "{}",
     /// The arguments to pass to the MCP server
     "args": {args},
     /// The environment variables to set
     "env": {env}
   }}
-}}"#
+}}"#,
+        command.display()
     )
 }