Improve C# type generation for required attributes

Update C# type generation template to throw ArgumentNullException for missing required int, double, and boolean attributes instead of using default values. Also, corrects the type check from 'float' to 'double' for consistency.

Author: Fellmonkey

templates/cli/lib/type-generation/languages/csharp.js.twig

@@ -120,21 +120,21 @@ public class <%= toPascalCase(collection.name) %>
                 if (attribute.array) {
                     -%> (map["<%- attribute.key %>"] as IEnumerable<object>)<%- !attribute.required ? '?' : '' %>.Select(e => Convert.ToInt32(e)).ToList()<%
                 } else {
-                    -%> map["<%- attribute.key %>"] != null ? Convert.ToInt32(map["<%- attribute.key %>"]) : (<%- attribute.required ? '0' : 'null' %>)<%
+                    -%> map["<%- attribute.key %>"] != null ? Convert.ToInt32(map["<%- attribute.key %>"]) : <% if (attribute.required) { %>throw new ArgumentNullException("<%- attribute.key %>", "Required attribute '<%- attribute.key %>' was null.")<% } else { %>null<% } %><%
                 }
             // FLOAT
-            } else if (attribute.type === 'float') {
+            } else if (attribute.type === 'double') {
                 if (attribute.array) {
                     -%> (map["<%- attribute.key %>"] as IEnumerable<object>)<%- !attribute.required ? '?' : '' %>.Select(e => Convert.ToDouble(e)).ToList()<%
                 } else {
-                    -%> map["<%- attribute.key %>"] != null ? Convert.ToDouble(map["<%- attribute.key %>"]) : (<%- attribute.required ? '0.0' : 'null' %>)<%
+                    -%> map["<%- attribute.key %>"] != null ? Convert.ToDouble(map["<%- attribute.key %>"]) : <% if (attribute.required) { %>throw new ArgumentNullException("<%- attribute.key %>", "Required attribute '<%- attribute.key %>' was null.")<% } else { %>null<% } %><%
                 }
             // BOOLEAN
             } else if (attribute.type === 'boolean') {
                 if (attribute.array) {
                     -%> (map["<%- attribute.key %>"] as IEnumerable<object>)<%- !attribute.required ? '?' : '' %>.Select(e => Convert.ToBoolean(e)).ToList()<%
                 } else {
-                    -%> map["<%- attribute.key %>"] != null ? Convert.ToBoolean(map["<%- attribute.key %>"]) : (<%- attribute.required ? 'false' : 'null' %>)<%
+                    -%> map["<%- attribute.key %>"] != null ? Convert.ToBoolean(map["<%- attribute.key %>"]) : <% if (attribute.required) { %>throw new ArgumentNullException("<%- attribute.key %>", "Required attribute '<%- attribute.key %>' was null.")<% } else { %>null<% } %><%
                 }
             // STRING, DATETIME, EMAIL
             } else if (attribute.type === 'string' || attribute.type === 'datetime' || attribute.type === 'email') {