fix: add proper error handling for Address.checksum() validation

[deseti]

• Address.checksum() can throw errors but should never return null/undefined
• Removed dead null checks that could never execute
• Added try-catch blocks to handle invalid addresses from data source
• Improves error messages for debugging invalid address data
• Affects 5 occurrences across 2 files

This prevents runtime crashes when encountering corrupted address data and provides better error reporting to help identify data quality issues.