graphics/dcmtk: Update 3.6.9 => 3.7.0, fix 5 CVEs

[alven]

Summary

Security:

• https://nvd.nist.gov/vuln/detail/CVE-2025-2357
• https://nvd.nist.gov/vuln/detail/CVE-2025-9732
• https://nvd.nist.gov/vuln/detail/CVE-2025-25472
• https://nvd.nist.gov/vuln/detail/CVE-2025-25474
• https://nvd.nist.gov/vuln/detail/CVE-2025-25475

Changelogs:

• https://github.com/DCMTK/dcmtk/compare/DCMTK-3.6.9...DCMTK-3.7.0

• Use dynamic SOVERSION
• Pet portclippy(1) and portfmt(1)

MFH: 2025Q4

Test Plan

For every {amd64} × {15.0, 14.3}:

• Successful poudriere testport

[alven]

Version-bump dependent ports