fix: replace deprecated *ngIf with @if control flow in OTP component

- Migrated all *ngIf directives to modern @if syntax in otp.component.html
- Updated email form, OTP entry, countdown display, and success message conditionals
- Resolves ngtsc deprecation warning 6385 for better Angular 17+ compatibility

src/app/auth/otp/otp.component.scss

@@ -0,0 +1,47 @@
+.otp-container {
+    max-width: 400px;
+    margin: 60px auto;
+    padding: 30px;
+    background: #fff;
+    border-radius: 16px;
+    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
+    text-align: center;
+
+    h2 {
+        margin-bottom: 20px;
+    }
+
+    input {
+        width: 100%;
+        padding: 10px;
+        margin: 10px 0;
+        font-size: 16px;
+    }
+
+    button {
+        width: 100%;
+        margin-top: 10px;
+        padding: 10px;
+        background-color: #007bff;
+        border: none;
+        color: white;
+        font-size: 16px;
+        border-radius: 8px;
+        cursor: pointer;
+
+        &:disabled {
+            background: #aaa;
+            cursor: not-allowed;
+        }
+    }
+
+    .success {
+        color: green;
+        font-weight: 600;
+    }
+
+    .message {
+        margin-top: 15px;
+        color: #555;
+    }
+}