Fix serializer permissions

[richardhallett]

Purpose

Don't return contacts on serialiser based on permissions.

closes: #1226

Approach

Check abilities before serialising.

Open Questions and Pre-Merge TODOs

N/A

Learning

N/A

Types 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)

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• Be humble in the language and feedback you give, ask don't tell.
• Consider using positive language as opposed to neutral when offering feedback. This is to avoid the negative bias that can occur with neutral language appearing negative.
• Offer suggestions on how to improve code e.g. simplification or expanding clarity.
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