agent: Include active file in recent history (#27914)

This happened because of two reasons:

- `Workspace::recent_navigation_history` didn't include the current file
- The context picker added the current file to a exclude list

The latter was actually intentional because we already show the file in
the suggested context, but now that we actually have mentions, it's just
inconvenient not to have it there.

Release Notes:

- N/A

crates/file_finder/src/file_finder.rs

@@ -468,15 +468,9 @@ impl Matches {
                 path: found_path.clone(),
                 panel_match: None,
             };
-            self.matches
-                .extend(currently_opened.into_iter().map(path_to_entry));
 
-            self.matches.extend(
-                history_items
-                    .into_iter()
-                    .filter(|found_path| Some(*found_path) != currently_opened)
-                    .map(path_to_entry),
-            );
+            self.matches
+                .extend(history_items.into_iter().map(path_to_entry));
             return;
         };