Update DR Congo flag with working one

[s-alad]

General

**Description: Update the flag of the democratic republic of congo to a working version from the same flagpedia website.**

Type of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have updated the documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed

Additional notes