Change discordId type from integer to string across frontend, backend, and API schema for consistency and proper validation.

frontend/src/app/pages/forms/discord-appeal/discord-appeal.component.ts

@@ -136,7 +136,7 @@ export class DiscordAppealComponent implements OnInit {
       this.bannedUser = {
         isBanned: false,
         bannedUser: {
-          userId: 212303885988134914,
+          userId: '212303885988134914',
           reason: "This is a test punishment",
           name: "stijn",
           avatarUrl: "https://cdn.discordapp.com/avatars/212303885988134914/3a264be54ca7208d638a22143fc8fdb8.webp?size=160"
@@ -145,7 +145,7 @@ export class DiscordAppealComponent implements OnInit {
       this.nextPage();
       return
     }
-    this.appealService.getBannedUser(Number(this.discordId))
+    this.appealService.getBannedUser(this.discordId)
       .subscribe(user => {
         this.bannedUser = user
         this.nextPage();
@@ -178,7 +178,7 @@ export class DiscordAppealComponent implements OnInit {
       throw new Error('JWT subject is null, are you logged in?');
     }
     const appeal: DiscordAppeal = {
-      discordId: Number(this.discordId),
+      discordId: this.discordId,
       appeal: rawValue.appeal,
       email: rawValue.email,
     }