Revert "fix(vulnerability): use VendorSeverity fallback before top-level Severity field"

This reverts commit c7a6caf.

Author: DmitriyLewen

pkg/vulnerability/vulnerability.go

@@ -162,15 +162,6 @@ func (c Client) autoDetectSeverity(vulnID string, vuln *dbTypes.Vulnerability, d
 		return severity, severitySource
 	}
 
-	// Fall back to any available VendorSeverity source in AllSourceIDs priority order.
-	// This handles cases where neither the data source nor NVD have a severity entry.
-	for _, source := range vulnerability.AllSourceIDs {
-		if severity, ok := vuln.VendorSeverity[source]; ok {
-			onceWarn()
-			return severity.String(), source
-		}
-	}
-
 	if vuln.Severity == "" {
 		return dbTypes.SeverityUnknown.String(), ""
 	}