Restore file to original content when rejecting file recreated by agent (#29264)

Release Notes:

- Fixed a bug that could sometimes cause a file to be deleted when
rejecting an agent change.

crates/assistant_tools/src/read_file_tool.rs

@@ -134,7 +134,7 @@ impl Tool for ReadFileTool {
                 })?;
 
                 action_log.update(cx, |log, cx| {
-                    log.buffer_read(buffer, cx);
+                    log.track_buffer(buffer, cx);
                 })?;
 
                 Ok(result)
@@ -147,7 +147,7 @@ impl Tool for ReadFileTool {
                     let result = buffer.read_with(cx, |buffer, _cx| buffer.text())?;
 
                     action_log.update(cx, |log, cx| {
-                        log.buffer_read(buffer, cx);
+                        log.track_buffer(buffer, cx);
                     })?;
 
                     Ok(result)