[Non-BE] Resolve "JBM: SBA RS to FOA decoding triggers assert"

• Related issues: #904 (closed)
• Requested reviewers:

Reason why this change is needed

In JBM SBA to FOA decoding with rate switching the information about the subframing is not updated correctly, leading to an assert.

Description of the change

Fix update of the subframing in the SBA JBM RS case.

Affected operating points

• JBM SBA with RS to FOA decoding (fixes assert)
• Produced bitstream is BE compared to previous state (no encoder change).

Related to #904 (closed)