[BUG]: Wrong timezone conversion and mode not working when using Bun SQL

### Report hasn't been filed before.

- [x] I have verified that the bug I'm about to report hasn't been filed before.

### What version of `drizzle-orm` are you using?

0.40.0

### What version of `drizzle-kit` are you using?

0.30.5

### Other packages

bun@1.2.4

### Describe the Bug

When using `timestamp` with `bun-sql`, `date` mode is returning the date with my local timezone not in UTC.
Also, `string` mode it's returning a Date constructor.

### **Steps to reproduce it:**
```ts
import { drizzle } from 'drizzle-orm/bun-sql';

import { timestamp } from 'drizzle-orm/pg-core';

createdAt: timestamp('created_at').notNull().defaultNow(),
```

**Value in Drizzle Studio:**

**Value after query:**
`2025-03-24T19:53:17.000Z`

### Expected behavior
The value should return the UTC time (`2025-03-24T22:53:17.725Z`), like other drivers.

Example using `drizzle-orm/node-postgres`:

---
The other problem that is occurring is that when using `mode: string`, it is still returning a Date constructor.
**Fun fact:** the date is returning with the correct time zone in this mode 😄

### **Steps to reproduce it:**
```ts
createdAt: timestamp('created_at', { mode: 'string' }).notNull().defaultNow(),
```

**Value after query:**

### Expected behavior
The value should return a string. Following is an example using `drizzle-orm/node-postgres`.