Adjust test suite wrt. changes in GUI behaviour when a device cannot be upgraded.

Refs: #5623

features/step_definitions/usb.rb

@@ -625,7 +625,7 @@ end
 
 Then /^a suitable USB device is (?:still )?not found$/ do
   next if @skip_steps_while_restoring_background
-  @screen.wait("TailsInstallerNoDevice.png", 60)
+  @screen.wait("TailsInstallerNoQEMUHardDisk.png", 30)
 end
 
 Then /^the "(?:[[:alpha:]]+)" USB drive is selected$/ do

features/usb_install.feature

@@ -11,16 +11,18 @@ Feature: Installing Tails to a USB drive, upgrading it, and using persistence
     And I start Tails from DVD with network unplugged and I login
     And I create a 4 GiB disk named "pristine"
     And I plug USB drive "pristine"
-    And I try to "Upgrade from ISO" USB drive "pristine"
-    But I am told that the destination device cannot be upgraded
+    And I start Tails Installer in "Upgrade from ISO" mode
+    Then a suitable USB device is not found
+    And I am told that the destination device cannot be upgraded
 
   Scenario: Try to "Clone & Upgrade" Tails to a pristine USB drive
     Given a computer
     And I start Tails from DVD with network unplugged and I login
     And I create a 4 GiB disk named "pristine"
     And I plug USB drive "pristine"
-    And I try a "Clone & Upgrade" Tails to USB drive "pristine"
-    But I am told that the destination device cannot be upgraded
+    And I start Tails Installer in "Upgrade from ISO" mode
+    Then a suitable USB device is not found
+    And I am told that the destination device cannot be upgraded
 
   Scenario: Try to "Upgrade from ISO" Tails to a USB drive with GPT and a FAT partition
     Given a computer
@@ -29,8 +31,9 @@ Feature: Installing Tails to a USB drive, upgrading it, and using persistence
     And I create a 4 GiB disk named "gptfat"
     And I create a gpt partition with a vfat filesystem on disk "gptfat"
     And I plug USB drive "gptfat"
-    And I try to "Upgrade from ISO" USB drive "gptfat"
-    But I am told that the destination device cannot be upgraded
+    And I start Tails Installer in "Upgrade from ISO" mode
+    Then a suitable USB device is not found
+    And I am told that the destination device cannot be upgraded
 
   Scenario: Try to "Clone & Upgrade" Tails to a USB drive with GPT and a FAT partition
     Given a computer
@@ -38,8 +41,9 @@ Feature: Installing Tails to a USB drive, upgrading it, and using persistence
     And I create a 4 GiB disk named "gptfat"
     And I create a gpt partition with a vfat filesystem on disk "gptfat"
     And I plug USB drive "gptfat"
-    And I try a "Clone & Upgrade" Tails to USB drive "gptfat"
-    But I am told that the destination device cannot be upgraded
+    And I start Tails Installer in "Upgrade from ISO" mode
+    Then a suitable USB device is not found
+    And I am told that the destination device cannot be upgraded
 
   Scenario: Try installing Tails to a too small USB drive
     Given a computer