HRTF improvements to BASOP

Revision and improvements to HRTF changes related to:

• ivas-codec-pc/ivas-codec!1698 (merged) - issue #1900 (closed)
• ivas-codec-pc/ivas-codec!1741 (merged) - issue #1928 (closed)
• ivas-codec-pc/ivas-codec!1804 (merged)

This MR is to be merged to !2221 (merged).