Fixes frame string formatting for transcoding

[jakubjezek001]

Changelog Description

Ensures the frame string used for transcoding includes the correct padding,
based on the collection's padding attribute. This resolves issues where
the output file sequence name was not correctly formatted, leading to
transcoding failures.

Additional info

I had found out about the issue during batchdelivery tests

Testing notes:

1. only able to test this on higher then 4padding image sequence

[BigRoy]

Isn't this exactly what the --framepadding argument is for in oiiotool.

I understand it's optional, but since it's a simple override optional why not just use that?

See: https://openimageio.readthedocs.io/en/latest/oiiotool.html#frame-sequences

Pretty sure I also used that and tested that in: #1217

[iLLiCiTiT]

If --framepadding works, then please use that instead.

[rdelillo]

Approving this PR as this code works and fixes the issue.
If that's a urgent/critical bugfix, I believe this patch is good enough.

Now as flagged, there is a specific --framepadding argument that could be used here.
Just wanted to add that from my tests, --framepadding needs to be there along --frames.

# Works
oiiotool.exe --info -v -i:infoformat=xml C:/Users/robin/output.948845-948869%07.exr

# Works
oiiotool.exe --info -v -i:infoformat=xml C:/Users/robin/output.#.exr --frames 948845-948869 --framepadding 7

# Does NOT work
oiiotool.exe --info -v -i:infoformat=xml C:/Users/robin/output.948845-948869.exr --framepadding 7