🧹Provide Unit Tests for `GetMapRequestHandler` and `GetMapRequestValidator`

[mathew-odwyer]

Checklist

• I have not removed the 🧹 emoji from the title.
• I have confirmed that this task is not already tracked under another tech debt or refactor issue.
• This does not represent a user-facing feature request or bug report, but an internal improvement.
• For maintainers: I have updated the projects and milestones if needed.

Description

We should write unit tests for GetMapRequestHandler and GetpMapRequestValidator.

Impact

This will provide further test coverage for the Web API.