ERS IM packet parsing ignores sample flags and activity task bytes

[kautlenbachs]

Excerpt from code, they are not used.
During the testing this did not trigger, but the echo invalid bit was always '0'

if (!(echo_meta.sample_flags & 0x50) || echo_meta.activity_task != 0xAA) {
            LOGW << "Sample flag not set but transferring data.";
        }