fix: Failing tests related to checking invalid input in formFields

This commit fixes a failing test case that was testing for an invalid
input in formFields with non string value but since that type of value
is now supported, the test case was broken.

recipe/emailpassword/formFieldValidator_test.go

@@ -168,8 +168,8 @@ func TestInvalidAPIInputForFormFields(t *testing.T) {
 					},
 				},
 			},
-			expected:   "formFields must be an array of objects containing id and value of type string",
-			fieldError: false,
+			expected:   "Field is not optional",
+			fieldError: true,
 		},
 		{
 			input: map[string]interface{}{
@@ -179,8 +179,8 @@ func TestInvalidAPIInputForFormFields(t *testing.T) {
 					},
 				},
 			},
-			expected:   "formFields must be an array of objects containing id and value of type string",
-			fieldError: false,
+			expected:   "Field is not optional",
+			fieldError: true,
 		},
 		{
 			input: map[string]interface{}{