Add missing ClinVar pathogenicity values

[kubacech]

Summary

• Add low penetrance combinations (likely pathogenic, low penetrance, pathogenic, low penetrance)
• Add VUS sub-classifications (vus-high, vus-mid, vus-low) from ClinVar 2025+
• Add conflicting classifications of oncogenicity
• Add additional somatic tiers (tier iii - uncertain significance, tier iv - benign/likely benign)

These values are encountered when processing recent ClinVar XML releases and cause InvalidDataException without this fix.