avoid std::allocator<const T>

std::vector<const T> uses std::allocator<const T>, which is an
undocumented libc++ extension to the C++ standard library. The extension
was removed in llvm.org/PR96319. Use an ordinary non-const T instead.

Bug: 349681543
Test: m bluetooth_test_gdx_unit a2dp_codec_info_fuzz
Test: m MODULES-IN-packages-modules-Bluetooth
Flag: EXEMPT, refactor to fix build failure
Change-Id: I8ddaebf5727da130c46860fae2a47d2699523227