ffprobe returns error on mpeg-ts inputs

When the input video is a TS file, ffprobe (e.g., ffprobe -v error -select_streams v:0 -show_entries stream=r_frame_rate -of default=noprint_wrappers=1:nokey=1 input.ts) returns r_frame_rate twice, e.g.,
"
30/1
30/1
", causing the following line to fail, https://github.com/google/uvq/blob/main/utils/probe.py#L115. Error message received: "Error getting r_frame_rate for input.ts: too many values to unpack (expected 2)". The code only expects one single output, e.g., "30/1".

Start in utils/probe.py at line 115 and reproduce the issue with the ffprobe command from the report on an MPEG-TS input. Trace how the r_frame_rate output is parsed, then verify that the probe handles the repeated output without the unpacking error and still returns the expected frame rate.

Written by the indexing model from the issue text.