feat(types): extended chatMessage to support enhanced ux (#699)

## Problem
Render modified files per prompt separately into a new component with
undo button per file and undoall buttons.

## Solution
Since, the chatMessage already sends modified files and buttons etc.
extending the same chatMessage so the new mynah-ui component can also
get the chatMessage when these new fields are set.

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## License

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license.

Author: sacrodge

types/chat.ts

@@ -203,6 +203,10 @@ export interface ChatMessage {
             selected?: boolean | undefined
         }[]
     }
+    modifiedFilesTracker?: {
+        title?: string
+        removeFile?: boolean
+    }
 }
 
 /**