Remove old warning from Sandstorm import board data loss, because bug has been already fixed.

Thanks to aputsiaq and xet7 !

client/components/import/import.jade

@@ -15,9 +15,6 @@ template(name="importTextarea")
     p: label(for='import-textarea') {{_ instruction}} {{_ 'import-board-instruction-about-errors'}}
     textarea.js-import-json(placeholder="{{_ 'import-json-placeholder'}}" autofocus)
       | {{jsonText}}
-    if isSandstorm
-      h1.warning {{_ 'import-sandstorm-backup-warning'}}
-      p.warning {{_ 'import-sandstorm-warning'}}
     input.primary.wide(type="submit" value="{{_ 'import'}}")
 
 template(name="importMapMembers")

i18n/en.i18n.json

@@ -348,8 +348,6 @@
   "import-board-c": "Import board",
   "import-board-title-trello": "Import board from Trello",
   "import-board-title-wekan": "Import board from previous export",
-  "import-sandstorm-backup-warning": "Do not delete data you import from original exported board or Trello before checking does this grain close and open again, or do you get Board not found error, that means data loss.",
-  "import-sandstorm-warning": "Imported board will delete all existing data on board and replace it with imported board.",
   "from-trello": "From Trello",
   "from-wekan": "From previous export",
   "import-board-instruction-trello": "In your Trello board, go to 'Menu', then 'More', 'Print and Export', 'Export JSON', and copy the resulting text.",