Check NumFramesDecoded when using intermediate

[tklam]

It happens that after AcceptWaveform() the number of frames decoded can still be 0 for a few passes. If NumFraamesDecoded() is not considered, the following error will occur:

ERROR (fcgi-nnet3-decoder[5.2.68~1391-aedc2]:GetLattice():online-nnet3-decoding.cc:57) You cannot get a lattice if you decoded no frames.

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[tklam]

I signed it!

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CLAs look good, thanks!

[realill]

I will merge it if someone will validate that it is working.