fix: suppress false-positive Snyk hardcoded-password finding in TestError

Snyk Code flagged the dummy test fixture value as a hardcoded password
(CWE-798). Annotate it with a deepcode ignore comment since it's a test
value, not a real credential. Verified with snyk code test and
trufflehog that no active/real secrets remain.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: reeshika-h

contentstack/src/test/java/com/contentstack/sdk/TestError.java

@@ -283,6 +283,7 @@ public void testNetworkErrorScenario() {
     public void testValidationErrorScenario() {
         HashMap<String, Object> validationErrors = new HashMap<>();
         validationErrors.put("email", "Invalid email format");
+        // deepcode ignore HardcodedPassword: test fixture value, not a real secret
         validationErrors.put("password", "Password too short");
 
         error.setErrorMessage("Validation failed");