When not provided set viewerConfigInputStreamProvider from viewerConfigFilePath

Otherwise there are cases where we are missing the viewer config in the trace which means we fail to decode the protolog in Winscope.

Flag: EXEMPT bug fix
Bug: 369052956
Test: Capture a protolog trace from Winscope
Change-Id: Ibdb04549b9e427790d83838010a99145cb2bde1e