tmux in wsl not responding to mouse events in win10 integrated terminal

[tw-space]

• VSCode Version: 1.45.0 (user setup)
• VSCode Insider Version: 1.46.0-insider (user setup)
• OS Version: Windows_NT x64 10.0.18363 (win10)

==Setup (fresh)==

1. Enable WSL
2. Install Windows Terminal & Ubuntu from Store
3. Install zsh and oh-my-zsh & enable as default shell
4. Install tmux & configure .tmux.conf with set -g mouse on
5. Configure VSCode to start with WSL ("terminal.integrated.shell.windows": "C:\\WINDOWS\\system32\\WSL.exe")
6. Test "terminal.integrated.windowsEnableConpty" both false and true
7. Test both VSCode and VSCode Insiders with no extensions

==Repro steps==

1. Launch VSCode > zsh launches in integrated terminal
2. Run tmux
3. Type tmux bind key (Ctrl+b default) then :split > pane splits
4. Observe focus is in new pane (type stuff to confirm)
5. Press enter several times until pane overflows
6. TRY scrolling pane up with mouse to see older lines
7. Also TRY clicking in previous pane to switch active pane

==Result==

1. tmux panes not responding to scroll events
2. tmux not switching active pane with click events

==Other observations==

1. tmux in wsl working as expected (both scroll & active pane switch) in Windows Terminal (i.e. not in VSCode)
2. tmux in zsh working as expected in Mac VSCode terminal with near-identical configuration
3. Can select & copy text from tmux in win10 vscode
4. Issue seems similar/identical to #29814, which was closed suspecting cause as winpty. But issue continues to repro with conpty.

Does this issue occur when all extensions are disabled?: Yes

[Tyriar]

/duplicate #96058