Support bare worktrees where worktree does not have its own .git file

This was on oversight on my part: I assumed that the --work-tree arg was
always intended for use with linked worktrees which have a .git file
pointing back to the repo.

I'm honestly confused now: seems like there are three kinds of worktrees:
* the main worktree of a non-bare repo
* a linked worktree (with its own gitdir in the repo's worktrees/ dir)
* a random folder which you specify as a worktree with the --work-tree arg

I'm pretty sure the --work-tree arg is only intended to be used with this
third kind or workree

pkg/integration/tests/worktree/dotfile_bare_repo.go

@@ -11,7 +11,7 @@ import (
 var DotfileBareRepo = NewIntegrationTest(NewIntegrationTestArgs{
 	Description:  "Open lazygit in the worktree of a dotfile bare repo and add a file and commit",
 	ExtraCmdArgs: []string{"--git-dir={{.actualPath}}/.bare", "--work-tree={{.actualPath}}/repo"},
-	Skip:         true,
+	Skip:         false,
 	// passing this because we're explicitly passing --git-dir and --work-tree args
 	UseCustomPath: true,
 	SetupConfig:   func(config *config.AppConfig) {},