[Bug]: Custom Emoji Picker broken (invalid query parameter)

Description:

Since Version 8.0.0. currently 8.2.1.

When using the Web UI, it sends the following Request to the API to list custom emojis:
https://<URL>/api/v1/emoji-custom.list?query=
This results in the API responding with

{
    "success": false,
    "error": "Invalid query parameter provided: \"\" [error-invalid-query]",
    "errorType": "error-invalid-query",
    "details": {
        "helperMethod": "parseJsonQuery"
    }
}

When I do a cURL to https:///api/v1/emoji-custom.list, it works flawlessly.

Either the UI should omit the query parameter completely, or the backend should change an empty parameter (query=) to {}.

The Emojis are not gone and can still be changed/added/removed from the /admin/emoji panel.

Let me know if there is anything I can do.

Steps to reproduce:

1. Open Custom Emoji Picker: Will show no emojis.
2. Check Browser Network Call to https://<URL>/api/v1/emoji-custom.list

Expected behavior:

Custom Emojis work

Actual behavior:

Server Setup Information:

• Version of Rocket.Chat Server: 8.2.1
• License Type: Community
• Number of Users: 100+
• Operating System: Container Image
• Deployment Method: Helm Chart on Kubernetes
• Number of Running Instances: 1
• DB Replicaset Oplog: 8.2.3 / unknown (oplog Disabled)
• NodeJS Version: v22.16.0
• MongoDB Version: 8.2.3 / unknown (oplog Disabled)

Client Setup Information

• Desktop App or Browser Version: Same behavior on any browser
• Operating System: -

Additional context

Relevant logs:

{"level":40,"time":"2026-03-24T09:49:24.036Z","pid":1,"hostname":"rocketchat-rocketchat-66c65d9ff6-xzrfk","name":"DeprecationWarning","section":"API","msg":"The usage of the \"query\" parameter in endpoint \"/api/v1/emoji-custom.list\" breaks the security of the API and can lead to data exposure. It has been deprecated and will be removed in the version 9.0.0.","endpoint":"/api/v1/emoji-custom.list","parameter":"query","version":"9.0.0"}
{"level":40,"time":"2026-03-24T09:49:24.036Z","pid":1,"hostname":"rocketchat-rocketchat-66c65d9ff6-xzrfk","name":"API","msg":"Invalid query parameter provided","query":"","err":{"type":"SyntaxError","message":"Unexpected end of JSON input","stack":"SyntaxError: Unexpected end of JSON input\n    at JSON.parse (<anonymous>)\n    at Object.EJSON.parse (/app/bundle/programs/server/npm/node_modules/ejson/index.js:933:35)\n    at parseJsonQuery (app/api/server/helpers/parseJsonQuery.ts:119:18)\n    at APIClass.parseJsonQuery (app/api/server/ApiClass.ts:248:10)\n    at Object.parseJsonQuery (app/api/server/ApiClass.ts:915:40)\n    at Object.get (app/api/server/v1/emoji-custom.ts:37:33)\n    at Object._internalRouteActionHandler (app/api/server/ApiClass.ts:923:39)\n    at processTicksAndRejections (node:internal/process/task_queues:105:5)\n    at /app/bundle/programs/server/npm/node_modules/@rocket.chat/http-router/src/Router.ts:256:21\n    at dispatch (/app/bundle/programs/server/npm/node_modules/hono/dist/cjs/compose.js:44:17)\n    at dispatch (/app/bundle/programs/server/npm/node_modules/hono/dist/cjs/compose.js:44:17)\n    at app/api/server/middlewares/tracer.ts:20:4\n    at dispatch (/app/bundle/programs/server/npm/node_modules/hono/dist/cjs/compose.js:44:17)\n    at app/api/server/middlewares/metrics.ts:22:3\n    at dispatch (/app/bundle/programs/server/npm/node_modules/hono/dist/cjs/compose.js:44:17)\n    at app/api/server/middlewares/logger.ts:30:3\n    at dispatch (/app/bundle/programs/server/npm/node_modules/hono/dist/cjs/compose.js:44:17)\n    at app/api/server/middlewares/cors.ts:18:4\n    at dispatch (/app/bundle/programs/server/npm/node_modules/hono/dist/cjs/compose.js:44:17)\n    at dispatch (/app/bundle/programs/server/npm/node_modules/hono/dist/cjs/compose.js:44:17)\n    at /app/bundle/programs/server/npm/node_modules/hono/dist/cjs/hono-base.js:323:25\n    at /app/bundle/programs/server/npm/node_modules/@rocket.chat/http-router/src/middlewares/honoAdapterForExpress.ts:15:18"}}

Start with app/api/server/v1/emoji-custom.ts and the parseJsonQuery call shown in app/api/server/helpers/parseJsonQuery.ts, then trace the request from the Custom Emoji Picker. Reproduce the empty query= request and compare it with the working request that omits the parameter. Done means the picker lists custom emojis without triggering the invalid-query error.