message: core: fix unit test
diff: @@ -34,7 +34,7 @@ TEST(MavlinkStatustextHandler, Severities)
  TEST(MavlinkStatustextHandler, WrongSeverity)
  {
  auto result = MavlinkStatustextHandler::severity_str(static_cast<MAV_SEVERITY>(255));
  - EXPECT_FALSE("unknown severity");
  + EXPECT_EQ(result, "unknown severity");
  }
  TEST(MavlinkStatustextHandler, SingleStatustextWithNull)
  