Fix NVIDIA GPU serial number format extraction

Extract decimal serial numbers from devname parameters (e.g., "SXM5_SN_1653925027099")
instead of hex PCIe Device Serial Numbers. This provides the correct GPU serial
numbers as they appear in NVIDIA diagnostics tooling.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

internal/parser/vendors/nvidia/parser_test.go

@@ -119,27 +119,3 @@ func findSubstring(s, substr string) bool {
 	return false
 }
 
-func TestFormatGPUSerial(t *testing.T) {
-	tests := []struct {
-		input    string
-		expected string
-	}{
-		{
-			input:    "14-17-dc-65-77-2d-b0-48",
-			expected: "48:B0:2D:77:65:DC:17:14",
-		},
-		{
-			input:    "f2-fd-85-e0-2f-2d-b0-48",
-			expected: "48:B0:2D:2F:E0:85:FD:F2",
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.input, func(t *testing.T) {
-			result := formatGPUSerial(tt.input)
-			if result != tt.expected {
-				t.Errorf("formatGPUSerial(%s) = %s, want %s", tt.input, result, tt.expected)
-			}
-		})
-	}
-}