fix: Back from Settings never lands on Settings itself (closes #481)

The recovery phrase and delete wallet screens take themselves off the
Back stack when left, so Settings, one of those screens, then the
settings gear leaves Settings under the Settings now showing. A reopened
popup restores the same stack, cut at the screen the gear left. Back
then showed Settings again and seemed to do nothing.

goBack() now skips any entry for the screen already showing before it
pops its target. Jest tests drive the gear and then Back for the
recovery phrase screen, once and twice over, for both delete screens,
and after a reopen.

Model: opus-5-5

tests/backNavigation.test.js

@@ -52,6 +52,7 @@ const {
     resetRenderedViews,
 } = require("../src/popup/viewRouter");
 const { state } = require("../src/shared/state");
+const { restorableStack } = require("../src/shared/persistedState");
 
 const ADDRESS = "0x1111111111111111111111111111111111111111";
 const TOKEN = "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48";
@@ -209,6 +210,23 @@ describe("Back onto a view the reopened popup never rendered", () => {
     });
 });
 
+// https://git.eeqj.de/sneak/AutistMask/issues/481. Settings, the recovery
+// phrase or delete wallet screen, the gear, then a reopen: the restored stack
+// is cut at the screen the gear left, which leaves Settings under the Settings
+// the popup reopens onto.
+describe("Back from Settings reopened over its own entry", () => {
+    test.each(["show-phrase", "delete-wallet-confirm"])(
+        "goes to the screen under it after leaving %s",
+        (left) => {
+            const stored = ["main", "settings", left];
+            reopenedOn("settings", restorableStack(stored, "settings"));
+            goBack();
+            expect(calls).toEqual(["main"]);
+            expect(state.currentView).toBe("main");
+        },
+    );
+});
+
 // The guards are restoreView()'s, so a popped view whose backing data is
 // gone lands on Home rather than on an empty template.
 describe("Back onto a view whose backing data is gone", () => {