btm_iso: Remove assert on CIS data path created

Now, when audio data are provided from other thread, we need to accept
that there might be a race when Releasing has been initiated by peer device

04-11 17:01:09.080527 14199 14257 I bt_stack: [INFO:client_parser.cc(112)] ASE status: 	ASE id: 0x01	ASE state: Releasing (0x06)
04-11 17:01:09.080824 14199 14257 I bluetooth: packages/modules/Bluetooth/system/bta/le_audio/state_machine.cc:281 ProcessGattNotifEvent:  cd:05:9c:5b:5d:31 , ASE id: 1, state changed STREAMING (0x04) -> RELEASING (0x06)
04-11 17:01:09.080929 14199 14257 I bt_stack: [INFO:devices.h(266)] SetTargetState target state: STREAMING (0x04) new target state: IDLE (0x00)
04-11 17:01:09.092961  9467 10264 E gralloc4: Empty SMPTE 2094-40 data
04-11 17:01:09.103612  9467 10264 E gralloc4: Empty SMPTE 2094-40 data
04-11 17:01:09.114462 14199 15347 F bt_stack: [FATAL:btm_iso_impl.h(428)] Assert failed: iso->state_flags & kStateFlagHasDataPathSet. Data path not set for handle: 0x0060

Bug: 228809876
Bug: 150670922
Test: atest --host net_test_btm_iso
Change-Id: Ibb88bb5cd9853ac6e6c5940d5be446b355633969