Fix for heap buffer overflow issue flagged by fuzzer test.

OOB write occurs when a value is assigned to a buffer index which is greater than the buffer size. Adding a check on buffer bounds fixes the issue.

Similar checks have been added wherever applicable on other such methods of the class.

Bug: 243463593
Test: Build mtp_packet_fuzzer and run on the target device
Change-Id: Icd0f2307803a1a35e655bc08d9d4cca5e2b58a9b
Merged-In: Icd0f2307803a1a35e655bc08d9d4cca5e2b58a9b
(cherry picked from commit a669e34b)