Escape markdown in tools' ui_text (#27502)

Escape markdown in tools' `ui_text`

<img width="628" alt="Screenshot 2025-03-26 at 10 43 23 AM"
src="https://github.com/user-attachments/assets/bb694821-aae7-4ccf-a35a-a3317b0222d5"
/>


Release Notes:

- N/A

crates/assistant_tools/src/fetch_tool.rs

@@ -13,6 +13,7 @@ use project::Project;
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 use ui::IconName;
+use util::markdown::MarkdownString;
 
 #[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Clone, Copy)]
 enum ContentType {
@@ -133,7 +134,7 @@ impl Tool for FetchTool {
 
     fn ui_text(&self, input: &serde_json::Value) -> String {
         match serde_json::from_value::<FetchToolInput>(input.clone()) {
-            Ok(input) => format!("Fetch `{}`", input.url),
+            Ok(input) => format!("Fetch {}", MarkdownString::escape(&input.url)),
             Err(_) => "Fetch URL".to_string(),
         }
     }