Resolves issue #1874, Preserve both CNA modified-date bounds in CVE query filters.

[david-rocca]

Closes Issue #1874 and #1328

Summary

Fixes cna_modified=true filtering so time_modified.gt and time_modified.lt are both preserved in the Mongo query for /api/cve and /api/cve_cursor.

Important Changes

src/controller/cve.controller/cve.controller.js

• Initializes the CNA provider metadata date query object once per request.
• Adds $gt and $lt to the same query object instead of overwriting one bound.

test/unit-tests/cve/cveGetAllTest.js

• Added query-construction regression tests for /api/cve and /api/cve_cursor.

test/integration-tests/cve/getCveCnaModifiedTest.js

• Added endpoint coverage proving only CVEs inside the requested CNA modified-date window are returned.

Testing

Steps to manually test updated functionality, if possible

• 1) Call /api/cve?time_modified.gt=<start>&time_modified.lt=<end>&cna_modified=true and verify only in-window CNA modified records return.
• 2) Call /api/cve_cursor?time_modified.gt=<start>&time_modified.lt=<end>&cna_modified=true and verify only in-window CNA modified records return.