…elastic#247014)

Related to elastic#239968.

## Summary

Optimizes the `QueryService` to use the original request when operating
from the default space, only creating a fake request bound to the
default space when the request originates from a non-default space.

## Problem

Previously, `QueryService.getClientWithRequest()` was unconditionally
creating a fake request bound to the default space for the rules client,
even when the original request was already coming from the default
space. This was unnecessary overhead.

## Solution

- Added `SpacesPluginStart` as an optional dependency in
`StreamsPluginStartDependencies`
- Modified the logic to check the current space ID:
- If the request is from the **default space** → use the original
request
- If the request is from a **non-default space** → use the fake request
bound to the default space

(cherry picked from commit 1a8a9dd)

# Conflicts:
#	x-pack/platform/plugins/shared/streams/server/lib/streams/assets/query/query_service.ts