several one-line panic, race, and logic fixes (#7766)

i18n/en.json

@@ -2171,6 +2171,10 @@
     "id": "api.team.import_team.parse.app_error",
     "translation": "Could not parse multipart form"
   },
+  {
+    "id": "api.team.import_team.no_import_from.app_error",
+    "translation": "Malformed request: importFrom field is not present."
+  },
   {
     "id": "api.team.import_team.unavailable.app_error",
     "translation": "Malformed request: filesize field is not present."