Fix regression where all uninitialized tracks are connected

[LinasKo]

Description

Apparently, external track ID must start with 1 and not 0.
I introduced the regression when refactoring how IDs are stored and generated inside ByteTrack, somewhere around Commit #4a7d9cea.

If this is not true, when minimum_consecutive_frames > 1, all objects where no traces are established get assigned an ID of 0, and are connected with a single trace. A bit odd. Not sure where this coupling comes from.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How has this change been tested, please provide a testcase or example of how you tested the change?

Colab

Any specific deployment considerations

None

Docs

• Docs updated? What were the changes:

[LinasKo]

Regression:

people-walking-out.mp4

Fixed:

people-walking-out.2.mp4

Edit: if this doesn't load, you can generate the same videos in the Colab.