TranscoderUtils.java line 134

I have the following crash on my app caused by LiTr lib:

```
Fatal Exception: java.lang.NullPointerException: Attempt to invoke virtual method 'long java.lang.Long.longValue()' on a null object reference
at android.media.MediaFormat.getLong(MediaFormat.java:855)
at com.linkedin.android.litr.utils.TranscoderUtils.estimateVideoTrackBitrate(TranscoderUtils.java:134)
...
```

Could you please fix it as it affected many of my app users?

**Extra Info:**
LiTr version: com.linkedin.android.litr:litr:1.5.5
Android OS: Different OS versions
Android device: Different Android devices

Start by reading TranscoderUtils.java around line 134 and tracing estimateVideoTrackBitrate's MediaFormat access. Done means the reported null-value crash no longer occurs for the affected case; the issue does not name a test or reproduction input to run.

Written by the indexing model from the issue text.