Resolves issue #1879, fixes date-only query filter sanitization.

[david-rocca]

Closes Issue #1879

Summary

This MR fixes toDate() date-only parsing so valid YYYY-MM-DD filters no longer throw ReferenceError, while invalid date-only values return the normal validation error.

Important Changes

src/utils/utils.js

• Defines a local dateStr in the date-only branch.
• Validates date-only strings with Luxon before converting them to UTC midnight.

test/unit-tests/utils/utilsTest.js

• Adds valid and invalid date-only sanitizer coverage.

test/integration-tests/cve/getCveDateTest.js

• Adds CVE endpoint regression coverage for date-only filters.

test/integration-tests/cve-id/getCveIdTest.js

• Adds CVE ID endpoint regression coverage for date-only filters.