codec2: BufferPoolClient: fix NPE in fetchBufferHandle if connection is null

Do a null pointer check before connection->fetch().

Bug: 344846184
Flag: EXEMPT bugfix
Test:
1.atest android.media.decoder.cts.AdaptivePlaybackTest
2.atest android.media.decoder.cts.DecoderTest

Change-Id: I30031b4abf46f920b708320ffa3fa9d1598027b4
1 file changed