DFT Stereo residual PLC, time_offset counter wraps around for burst errors

(Generic issue template)

Related to sa4/audio/ivas-basop#943 (closed)

A JBM test case results in a long burst error, which leads to a wrap-around of the counter time_offs in the DFT Stereo residual PLC. The output should be attenuated in stereo_dft_res_ecu_burst_att(), such that the frozen counter should not create a repetitive sound.