Handle missing percent values

[cweiske]

Description

Handle missing percent values in reports by setting them to the default value of 100%

Fixes userjack6880/Open-DMARC-Analyzer#112

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

I let it run on my server for several weeks.

Test Configuration:

• OS: Debian 13
• OS Kernel Version: 6.12.74+deb13+1-amd64
• Perl Version: v5.40.1
• SQL Variant: MariaDB
• SQL Version: 11.8.6-MariaDB

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• [] I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings