Fix remaining unit tests after translation changes

tests/unit/Router/RouterTest.php

@@ -85,7 +85,7 @@ class FrontRouterTest extends MailPoetTest {
     expect($result)->equals(
       array(
         404,
-        'Invalid router endpoint action.'
+        'Invalid router endpoint action'
       )
     );
   }

tests/unit/Subscribers/ImportExport/Export/ExportTest.php

@@ -228,7 +228,7 @@ class ExportTest extends MailPoetTest {
       $this->fail('Export did not throw an exception');
     } catch(\Exception $e) {
       expect($e->getMessage())
-        ->equals("Couldn't save export file on the server");
+        ->equals("The export file could not be saved on the server.");
     }
   }