Fix BMS endpoint and auth issues

scripts/bms-auth.sh

@@ -88,8 +88,8 @@ cmd_auth_refresh() {
 
   local response
   response=$(curl -sf -X POST "${BMS_API_BASE}/v2/security/refreshtoken" \
-    -H "Content-Type: application/json" \
-    -d "{\"AccessToken\":\"${access_token}\",\"RefreshToken\":\"${refresh_token}\"}") \
+    -F "AccessToken=${access_token}" \
+    -F "RefreshToken=${refresh_token}") \
     || { echo "Refresh failed, re-authenticating..." >&2; cmd_auth_login; return; }
 
   save_token "$response"