Extend one of the filtering tests to start on a commit other than the first

Enabling the filter selects the first entry in the filtered commits view. It's
useful to have a test that checks this, as I almost broke it in the following
commit (it needs an added FocusLine call in the setFiltering function in
filtering_menu_action.go).

pkg/integration/tests/filter_by_path/select_file.go

@@ -18,10 +18,12 @@ var SelectFile = NewIntegrationTest(NewIntegrationTestArgs{
 		t.Views().Commits().
 			Focus().
 			Lines(
-				Contains(`only filterFile`).IsSelected(),
+				Contains(`none of the two`).IsSelected(),
+				Contains(`only filterFile`),
 				Contains(`only otherFile`),
 				Contains(`both files`),
 			).
+			SelectNextItem().
 			PressEnter()
 
 		// when you click into the commit itself, you see all files from that commit

pkg/integration/tests/filter_by_path/shared.go

@@ -14,6 +14,8 @@ func commonSetup(shell *Shell) {
 
 	shell.UpdateFileAndAdd("filterFile", "new filterFile content")
 	shell.Commit("only filterFile")
+
+	shell.EmptyCommit("none of the two")
 }
 
 func postFilterTest(t *TestDriver) {