Add test to demonstrate a problem with custom patches and directories sharing a prefix

We had the same bug in the files panel, and fixed it in a5eec48b4b, but
forgot to make the equivalent change to the commit files panel.

pkg/integration/tests/patch_building/select_direcories_sharing_prefix.go

@@ -0,0 +1,59 @@
+package patch_building
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var SelectDirecoriesSharingPrefix = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Select directories sharing a prefix in the commit files view and add them to a custom patch",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig:  func(config *config.AppConfig) {},
+	SetupRepo: func(shell *Shell) {
+		shell.CreateFileAndAdd("foo/file", "file1 content")
+		shell.CreateFileAndAdd("foobar/file", "file2 content")
+		shell.Commit("first commit")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Commits().
+			Focus().
+			Lines(
+				Contains("first commit").IsSelected(),
+			).
+			PressEnter()
+
+		t.Views().CommitFiles().
+			IsFocused().
+			Lines(
+				Equals("▼ /").IsSelected(),
+				Equals("  ▼ foo"),
+				Equals("    A file"),
+				Equals("  ▼ foobar"),
+				Equals("    A file"),
+			).
+			SelectNextItem().
+			Press(keys.Universal.ToggleRangeSelect).
+			NavigateToLine(Contains("foobar")).
+			PressPrimaryAction().
+			Lines(
+				Equals("▼ /"),
+				Equals("  ▼ foo").IsSelected(),
+				Equals("    ● file").IsSelected(),
+				Equals("  ▼ foobar").IsSelected(),
+				/* EXPECTED:
+				Equals("    ● file"),
+				ACTUAL: */
+				Equals("    A file"),
+			)
+
+		t.Views().Information().Content(Contains("Building patch"))
+
+		t.Views().Secondary().Content(
+			/* EXPECTED:
+			Contains("foo/file").Contains("foobar/file"),
+			ACTUAL: */
+			Contains("foo/file").DoesNotContain("foobar/file"),
+		)
+	},
+})

pkg/integration/tests/test_list.go

@@ -382,6 +382,7 @@ var tests = []*components.IntegrationTest{
 	patch_building.RenamedFileWhole,
 	patch_building.ResetWithEscape,
 	patch_building.SelectAllFiles,
+	patch_building.SelectDirecoriesSharingPrefix,
 	patch_building.SpecificSelection,
 	patch_building.StartNewPatch,
 	patch_building.ToggleDirectory,