AWS Q chat history file change diff cannot open due to encoding

## Problem
Using AWS Q in VS Code, when clicking on a file change in the chat history, the file path isn't accessible due to encoding.
Example:
Error: Unable to resolve resource c:%5CUsers%5Cxxxxxx%5CDocuments%5CGitHub%5Cxxx-xxx-xxxxx-xxxxx%5Capi%5Csrc%5Cmodels.py

## Steps to reproduce the issue

## Expected behavior
Diff file view should open in VS Code. This worked correctly before the latest update to the Q plugin.

## System details (run `AWS: About` and/or `Amazon Q: About`)

- OS: Windows 11 - Windows_NT x64 10.0.22631
- Visual Studio Code version: 1.104.0
- AWS Toolkit version: 3.74.0
- Amazon Q version: 1.94.0

Reproduce the issue in VS Code on Windows using the listed Visual Studio Code, AWS Toolkit, and Amazon Q versions, then trace how the Amazon Q chat history diff link turns the Windows file path into a VS Code resource. Done means clicking a file change opens the diff view instead of producing an encoded-path resolution error.

Written by the indexing model from the issue text.