Harmonize extend_frm_*fx() and shrink_frm_*fx()
# Bug description The function pairs * `extend_frm_fx()` and `extend_frm_ivas_fx()` * `shrink_frm_fx()` and `shrink_frm_ivas_fx()` are almost identical (except from one scaling + `isSilence_ivas_fx()` vs. `isSilence_fx()`) - it should be feasible to harmonize them.
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