AudioPolicy : Add null pointer checks in AudioOutputDescriptor

Since profile is expected to be null for duplicate descriptors,
added null checks for all the usages of the profile

Bug: 306871374
Test: ./audiopolicy_fuzzer clusterfuzz-testcase-minimized-audiopolicy_fuzzer-5131786691608576
Change-Id: I9d40eef2624529ac1b514a176b2a2ca0535f9298