Fix test assertions to fail properly and add NXDOMAIN deduplication

- test_seo.py: Add assertIsNotNone before conditional to catch SEO extraction failures
- test_ssl.py: Add assertIsNotNone to ensure SSL data is captured from HTTPS URLs
- test_pip_provider.py: Assert jsonl_found variable to verify binary discovery
- dns plugin: Deduplicate NXDOMAIN records using seenResolutions map

Tests now fail when functionality doesn't work (no cheating).

Co-authored-by: Nick Sweeting <pirate@users.noreply.github.com>

archivebox/plugins/seo/tests/test_seo.py

@@ -119,11 +119,12 @@ class TestSEOWithChrome(TestCase):
                 self.assertNotIn('Traceback', result.stderr)
                 self.assertNotIn('Error:', result.stderr)
 
-                # example.com has a title, so we should get at least that
-                if seo_data:
-                    # Verify we got some SEO data
-                    has_seo_data = any(key in seo_data for key in ['title', 'description', 'og:title', 'canonical', 'meta'])
-                    self.assertTrue(has_seo_data, f"No SEO data extracted: {seo_data}")
+                # example.com has a title, so we MUST get SEO data
+                self.assertIsNotNone(seo_data, "No SEO data extracted from file or stdout")
+
+                # Verify we got some SEO data
+                has_seo_data = any(key in seo_data for key in ['title', 'description', 'og:title', 'canonical', 'meta'])
+                self.assertTrue(has_seo_data, f"No SEO data extracted: {seo_data}")
 
         except RuntimeError as e:
             if 'Chrome' in str(e) or 'CDP' in str(e):