[non-BE] Resolve "Decoder crash in MASA DTX bitrateswitch"

• Related issues: #1211 (closed)
• Requested reviewers:

Reason why this change is needed

• DTX logic is buggy resulting in inconsistencies between parameters like ivas_total_bitrate, element_bitrate and total_bitrate. Consequently, a crash is observed.

Description of the change

• Switch to active frame coding when the bitrate is high and the noise level is substantial.

Affected operating points

• IVAS DTX and bitrate switching conditions can be non-BE.