fix: one password-failure message across every screen (closes #172)

A rejected password was reported three different ways depending on which screen
you were on, including the fragment "Wrong password." which is not a sentence.
All six decryptWithPassword call sites now show the same full sentence.

Strings only -- a wrong password still fails closed on every screen and still
resolves no pending approval.

A test pins the invariant per call site: each decryptWithPassword call is walked
out to its enclosing try and forward to that block's catch, and the prose shown
there must equal the canonical sentence. Per-file matching was not enough, since
a file with two call sites kept passing while one of them diverged.

src/popup/views/confirmTx.js

@@ -422,7 +422,10 @@ function init(ctx) {
                 password,
             );
         } catch (e) {
-            showError("confirm-tx-password-error", "Wrong password.");
+            showError(
+                "confirm-tx-password-error",
+                "That password is incorrect. Please try again.",
+            );
             return;
         }