Crash when selectively staging last change

### Describe the bug

There's an off-by-one when you incrementally stage the last hunk of a file. maybe only if it's the last file in the list? anyway it happens to me constantly and I just pulled the latest version to try to fix, but it's still there.

### To Reproduce
Steps to reproduce the behavior:

have multiple files changed, filter by only unstaged, start staging hunks. i've seen this happen a lot, but not every time?

### Expected behavior

no crash

### Screenshots

```
panic: runtime error: index out of range [1] with length 0

goroutine 452 [running]:
github.com/jesseduffield/lazygit/pkg/commands/patch.headerInfo({0x40009220fb?, 0x4bc?})
github.com/jesseduffield/lazygit/pkg/commands/patch/parse.go:47 +0xd0
github.com/jesseduffield/lazygit/pkg/commands/patch.Parse({0x4000922000?, 0x4bd?})
github.com/jesseduffield/lazygit/pkg/commands/patch/parse.go:22 +0x2fc
github.com/jesseduffield/lazygit/pkg/gui/patch_exploring.NewState({0x4000922000, 0x4bd}, 0xffffffffffffffff, 0x40000f98c8, 0x40002ca5b0, 0x1)
github.com/jesseduffield/lazygit/pkg/gui/patch_exploring/state.go:56 +0x94
github.com/jesseduffield/lazygit/pkg/gui/controllers/helpers.(*StagingHelper).RefreshStagingPanel(0x400021c778, {{0x0?, 0x4000bba658?}, 0x10c16c?})
github.com/jesseduffield/lazygit/pkg/gui/controllers/helpers/staging_helper.go:67 +0x220
github.com/jesseduffield/lazygit/pkg/gui/controllers/helpers.(*RefreshHelper).Refresh.func2.13()
github.com/jesseduffield/lazygit/pkg/gui/controllers/helpers/refresh_helper.go:177 +0x3c
github.com/jesseduffield/lazygit/pkg/gui/controllers/helpers.(*RefreshHelper).Refresh.func2.1.2()
github.com/jesseduffield/lazygit/pkg/gui/controllers/helpers/refresh_helper.go:114 +0x80
github.com/jesseduffield/lazygit/pkg/gui/controllers/helpers.(*RefreshHelper).Refresh.func2.1.gowrap1.Safe.1()
github.com/jesseduffield/lazygit/pkg/utils/utils.go:69 +0x24
github.com/jesseduffield/lazygit/pkg/utils.SafeWithError(0x1e?)
github.com/jesseduffield/lazygit/pkg/utils/utils.go:80 +0x5c
github.com/jesseduffield/lazygit/pkg/utils.Safe(...)
github.com/jesseduffield/lazygit/pkg/utils/utils.go:69
created by github.com/jesseduffield/lazygit/pkg/gui/controllers/helpers.(*RefreshHelper).Refresh.func2.1 in goroutine 1
github.com/jesseduffield/lazygit/pkg/gui/controllers/helpers/refresh_helper.go:111 +0x110
```

### Version info:

```
╰─❯ lg --version
commit=, build date=, build source=nix, version=0.56.0, os=linux, arch=arm64, git version=2.51.2
╰─❯ git --version
git version 2.51.2
```

### Additional context
Add any other context about the problem here.

> [!NOTE]
> Please try updating to the latest version or [manually building](https://github.com/jesseduffield/lazygit/#manual) the latest `master` to see if the issue still occurs.