This PR was merged into the 5.4 branch.

Discussion
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[Config] Handle ignoreExtraKeys in config builder

| Q             | A
| ------------- | ---
| Branch?       | 5.x
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

Currently the config builder doesn't handle the `ignoreExtraKeys` option. This is an attempt to fix that.

#### TODO
- [x] Tests, but I was hoping for some initial feedback first

Commits
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e6d62fb396 Handle ignoreExtraKeys in config builder