I can't switch session from worktrees to local

### Short summary

I lost the option to switch from worktrees to local

### Affected version or release

1.1.9

### Installation context

_No response_

### What happened?

In latest Windows version 1.1.9, it removed the option for us to switch between local VS worktree. I want it back!
The worktree doesn't work for our projects as our repo has a lot of submodules. It's not convenient to checkcout a worktree. There's no way to build and test in a worktree. It's broken. Please bring the settings back.

### Steps to reproduce
**Before**:

**After**:

### Expected behavior
I can let Copilot just update my code in current branch, so I can build and test there.

### Additional context

_No response_

Reproduce the issue on Windows with version 1.1.9 and compare the Before and After screenshots. Trace the settings that choose between worktrees and the current local branch, then verify that the switching option is available and that Copilot can update the current branch for projects using submodules.

索引モデルが issue の本文から書いたものです。