Implement missing isModalSubmitInteraction typeguard in deno types

Added a type-guard function to check for modal submit interactions in deno types because I missed that before.

deno/utils/v10.ts

@@ -15,6 +15,7 @@ import type {
 	APIMessageComponentGuildInteraction,
 	APIMessageComponentInteraction,
 	APIMessageComponentSelectMenuInteraction,
+	APIModalSubmitInteraction,
 } from '../payloads/v10/mod.ts';
 import { ApplicationCommandType, ButtonStyle, ComponentType, InteractionType } from '../payloads/v10/mod.ts';
 
@@ -114,6 +115,20 @@ export function isInteractionButton(component: APIButtonComponent): component is
 	return ![ButtonStyle.Link, ButtonStyle.Premium].includes(component.style);
 }
 
+// Modal
+
+/**
+ * A type-guard check for modals submit interactions
+ *
+ * @param interaction - The interaction to check against
+ * @returns A boolean that indicates if the interaction is a modal submission
+ */
+export function isModalSubmitInteraction(
+	interaction: APIInteraction,
+): interaction is APIModalSubmitInteraction {
+	return interaction.type === InteractionType.ModalSubmit;
+}
+
 // Message Components
 
 /**