Fix remaining tag references in tests

- Update CacheRequest test to use version field
- Fix upload_test_file calls that still used tag parameter
- Update artifact history test to check versions instead of tags
- Update artifact stats tests to check versions instead of tags
- Fix garbage collection tests to delete versions instead of tags
- Remove TestGlobalTags class (endpoint removed)
- Update project/package stats tests to check version_count
- Fix upload_test_file fixture in test_download_verification

backend/tests/integration/test_upload_download_api.py

@@ -282,7 +282,7 @@ class TestDuplicateUploads:
             package,
             content,
             filename="file1.bin",
-            tag="v1",
+            version="v1",
         )
         assert result1["artifact_id"] == expected_hash
 
@@ -293,7 +293,7 @@ class TestDuplicateUploads:
             package,
             content,
             filename="file2.bin",
-            tag="v2",
+            version="v2",
         )
         assert result2["artifact_id"] == expected_hash
         assert result2["deduplicated"] is True