Resolve "[CLANG18] MSAN: use-of-uninitialized-value in lib_rend/lib_rend_fx.c:11230:9"

• Related issues: #2329 (closed)
• Requested reviewers: @kiene @multrus

Reason why this change is needed

• There is MSAN error.

Description of the change

• Change the check to check for memory being reserved instead of checking for length of memory being larger than 0.

Affected operating points

• BE

Closes #2329 (closed)