Fulfill queries partially outside max query window

Related: https://github.com/grafana/grafana/issues/83644

### Problem

Pyroscope limits the maximum time span of queries and if a query is larger than this window, it fails outright.

https://github.com/grafana/pyroscope/blob/38218a8e16b67af9c777003dd29878673918ebed/pkg/validation/validate.go#L317-L323

The complete failure is a somewhat jarring experience for users as there generally is data to we could serve, but we don't attempt to fulfill it.

### Solution

We can copy what we do when a query is partially outside a retention window and [trim the query time range](https://github.com/grafana/pyroscope/blob/38218a8e16b67af9c777003dd29878673918ebed/pkg/validation/validate.go#L294-L314) to satisfy the query length limit. The only drawback is deciding how to trim the query time range. We have three options:

1. Trim from the `start` side of the query
```
max query length: 1d

now-3d now-2d now-1d now
▼ ▼ ▼ ▼
requested range: [=======================]
truncated range: [=======]
▲ ▲ ▲ ▲
now-3d now-2d now-1d now
```
2. Trim from the `end` side of the query
```
max query length: 1d

now-3d now-2d now-1d now
▼ ▼ ▼ ▼
requested range: [=======================]
truncated range: [=======]
▲ ▲ ▲ ▲
now-3d now-2d now-1d now
```
3. Trim equally from `start` and `end`
```
max query length: 1d

now-3d now-2d now-1d now
▼ ▼ ▼ ▼
requested range: [=======================]
truncated range: [=======]
▲ ▲ ▲ ▲
now-3d now-2d now-1d now
```

Option 1 seems to be the most natural heuristic as it mimics the notion of "Let's start at some point in time and include results as far back as possible." Option 2 is the inverse of option 1, but feels slightly less natural. Option 3 is a compromise of the two, but is the least natural as it makes the resulting range highly unpredictable.

If we choose to implement this feature, we should also include a mechanism whereby we can signal to clients that the query range had to modified in a specific way to return results. This will help UIs warn users the query results aren't precisely what they asked for.