[#641] Ignore readOnly fields during validation

[roberlander2]

Description

This PR disables readOnly validation for requests.

Resolves #641

Review Time Estimate

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Type of changes

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• [x] Bug fix (non-breaking change which fixes an issue).
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Checklist:

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• [x] I have signed the Rokwire Contributor License Agreement (CLA). (Any contributor who is not an employee of the University of Illinois whose official duties include contributing to the Rokwire software, or who is not paid by the Rokwire project, needs to sign the CLA before their contribution can be accepted.)
• [x] I have updated the CHANGELOG.
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• [ ] My change requires updating the documentation.
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• [x] New and existing unit tests pass locally with my changes.
• [x] Any dependent changes have been merged and published in downstream modules.

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