Add updated error messages for domain mgmt contact info

src/registrar/forms/domain.py

@@ -125,19 +125,6 @@ class ContactForm(forms.ModelForm):
     class Meta:
         model = Contact
         fields = ["first_name", "middle_name", "last_name", "title", "email", "phone"]
-        error_messages = {
-            "first_name": {"required": "Enter your first name / given name."},
-            "last_name": {"required": "Enter your last name / family name."},
-            "title": {
-                "required": "Enter your title or role in your organization (e.g., Chief Information Officer)."
-            },
-            "email": {
-                "required": "Enter your email address in the required format, like name@example.com."
-            },
-            "phone": {
-                "required": "Enter your phone number."
-            },
-        }
         widgets = {
             "first_name": forms.TextInput,
             "middle_name": forms.TextInput,
@@ -161,11 +148,22 @@ class ContactForm(forms.ModelForm):
         for field_name in self.required:
             self.fields[field_name].required = True
         
+        # Set custom error messages
+        self.fields["first_name"].error_messages = {'required': 'Enter your first name / given name.'}
+        self.fields["last_name"].error_messages = {'required': 'Enter your last name / family name.'}
+        self.fields["title"].error_messages = {
+            'required': 'Enter your title or role in your organization (e.g., Chief Information Officer)'
+        }
+        self.fields["email"].error_messages = {
+            'required': 'Enter your email address in the required format, like name@example.com.'
+        }
+        self.fields["phone"].error_messages = {'required': 'Enter your phone number.'}
+
 
 class DomainSecurityEmailForm(forms.Form):
     """Form for adding or editing a security email to a domain."""
 
-    security_email = forms.EmailField(label="Security email", required=False)
+    security_email = forms.EmailField(label="Security email (optional)", required=False)
 
 
 class DomainOrgNameAddressForm(forms.ModelForm):