fix: stop omitting redundantly parenthesized licenses in CDX formatter (#3517)

Previously, a bug in the formatter would cause SPDX expressions that
were surrounded in redundant parentheses to be dropped instead of
normalized.

Signed-off-by: Will Murphy <willmurphyscode@users.noreply.github.com>

syft/license/license_test.go

@@ -20,6 +20,11 @@ func TestParseExpression(t *testing.T) {
 			expression: "MIT OR Apache-2.0",
 			want:       "MIT OR Apache-2.0",
 		},
+		{
+			name:       "accept redundant parentheses",
+			expression: "(MIT OR Apache-2.0)",
+			want:       "(MIT OR Apache-2.0)",
+		},
 		{
 			name:       "Invalid SPDX expression returns error",
 			expression: "MIT OR Apache-2.0 OR invalid",