Bass: Fix parsing BASE structure

Each time we get the field length from the remote, make sure we actually
received the proper amount of data. This eliminates the fatal errors when
the BASE data is truncated or badly formatted.

Bug: 328181940
Test: atest BluetoothInstrumentationTests
Flag: EXEMPT; Regression tests added
Change-Id: I5ba26f8bda55c94424024b1cd80e8e95dfebc610