handle array root element

An array to string conversion notice was thrown when the root element of
the thing being validated is an array.
bug #10123 handle array root element (greg0ire)

This PR was submitted for the 2.4 branch but it was merged into the 2.3 branch instead (closes #10123).

Discussion
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handle array root element

An array to string conversion notice was thrown when the root element of the thing being validated is an array.

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT

Commits
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17ed8bf handle array root element