Resolve "similar_alleles not being returned in correct order"

Description

[Describe changes/solution; problem description should be in issue]

Related issues

Closes #1897 (closed)

Notes to review (code/docs/QA)

Tests

General

• Tests have been added that prove my fix is effective or that my feature works
• Related tests have been modified/removed

Hypothesis testing:

• Soak testing has been done
• Distribution between positive / negative cases has been checked

Database

• Includes changes to database schema
• Includes necessary database migrations

Configuration

• Includes changes to configuration
• Includes configuration migration instructions in documentation

Merge checklist

• Self-review of code has been performed.
• Feature review and validation against specification has been performed (if applicable). Apply label: QAdone
• Need for documentation has been evaluated and, if necessary, updated. Apply label: docsdone
• Code and implementation has been reviewed by other core developer (including any changes based on initial review). Apply label: code reviewdone