Long PromQL expressions overflow the query editor and break the Metrics Query layout

### Description

When a long PromQL expression is pasted into the query input on the **Metrics Query** page, the query editor does not properly constrain or wrap the content.

The long query expands horizontally and causes the page layout to break.

### Steps to reproduce

1. Open GreptimeDB Dashboard.
2. Go to **Metrics Query**.
3. Paste a relatively long PromQL expression into the query input.
4. Observe the query editor and page layout.

https://github.com/user-attachments/assets/674571d4-3600-471b-ac43-067add895efd

Start at the frontend entry point for the Metrics Query page and reproduce the issue by pasting a long PromQL expression into the query input. Trace the query editor's layout and sizing styles; done means long expressions stay constrained without horizontal overflow or breaking the page layout.

Written by the indexing model from the issue text.