Fix flaky account history mockapi test

Add some extra time to for the login page to show to
improve stability of the test.

Author: Pururun

android/test/mockapi/src/main/kotlin/net/mullvad/mullvadvpn/test/mockapi/AccountHistoryMockApiTest.kt

@@ -36,6 +36,7 @@ class AccountHistoryMockApiTest : MockApiTest() {
         app.ensureLoggedIn()
         app.clickAccountCog()
         app.clickActionButtonByText("Log out")
+        app.waitForLoginPrompt()
         device.findObjectWithTimeout(By.res(LOGIN_INPUT_TEST_TAG)).click()
 
         // Assert