[yasar710]

Updates dtvcc_write_row to respect --utf8 and --latin1 command-line flags instead of defaulting to raw bytes. This resolves the encoding issue for CEA-708 subtitles reported in #2450.

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Reason for this PR:

• This PR adds new functionality.
• This PR fixes a bug that I have personally experienced or that a real user has reported and for which a sample exists.
• This PR is porting code from C to Rust.

Sanity check:

• I have read and understood the contributors guide.
• I have checked that another pull request for this purpose does not exist.
• If the PR adds new functionality, I've added it to the changelog. If it's just a bug fix, I have NOT added it to the changelog.
• I am NOT adding new C code unless it's to fix an existing, reproducible bug.

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{pull request content here}

[yasar710]

Hi, the CI checks are failing during the "Install dependencies" step with the error: "E: Package 'libgpac-dev' has no installation candidate". This seems to be a GitHub Actions environment issue and not related to the C code changes in this PR.