[BUG] D1 `EXISTS` Query Fails to Parse Bool

### Is there an existing issue for this?

- [X] I have searched the existing issues

### What version of `workers-rs` are you using?

0.5.0

### What version of `wrangler` are you using?

3.99.0

### Describe the bug

Using `.first` with this type of query fails to parse the result as a bool.
```rust
db
.prepare("SELECT EXISTS(SELECT 1 FROM users WHERE email = $1)")
.bind(&[email.to_string().into()])
.unwrap()
.first::(None)
.await
```

### Steps To Reproduce

1. Setup a d1 db with a schema that allows you to use an `exists` query
2. Attempt to run the code in the description

Parsing fails