Add Omit to the Summary Counts

🗣 Description

Add "Omit" to the summary counts. HTML output is unchanged, JSON output now looks like this:

Tested manually, worked as expected.

[x] This PR has an informative and human-readable title.
[x] Changes are limited to a single goal - eschew scope creep!
[x] If applicable, All future TODOs are captured in issues, which are referenced in the PR description.
[x] The relevant issues PR resolves are linked preferably via closing keywords.
[x] All relevant type-of-change labels have been added.
[x] I have read and agree to the CONTRIBUTING.md document.
[x] These code changes follow cisagov code standards.
[x] All relevant repo and/or project documentation has been updated to reflect the changes in this PR.
[x] Tests have been added and/or modified to cover the changes in this PR.
[x] All new and existing tests pass.

[x] This PR has been smoke tested to ensure main is in a functional state when this PR is merged.
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