Rasterio Coverage Requests Fail for GCS/VSI Paths Without Bbox Parameter

# Bug Report: Rasterio Coverage Requests Fail for GCS/VSI Paths Without Bbox Parameter

## Description

Coverage requests to rasterio providers using GDAL Virtual File System (VSI) paths (e.g., `/vsigs/` for GCS) succeed when a `bbox` parameter is included, but fail with `FileNotFoundError` when no `bbox` is specified.

The root cause is an early-return optimization in pygeoapi's rasterio provider that bypasses rasterio/GDAL for native format requests with no bands, subsets, or bbox (i.e a plain {collectionsid}/coverage?f=GTiff type call). This shortcut delegates to `util.read_data()`, which only recognizes `http://` and `s3://` as remote paths and treats all other paths (including `/vsigs/`) as local file paths. GDAL VSI paths cannot be opened with `Path.open("rb")`, causing the failure.

Requests *with* a bbox parameter continue through the full rasterio/GDAL code path, which correctly handles VSI paths, so they succeed.

## Steps to Reproduce

1. Configure a pygeoapi coverage collection with a rasterio coverage provider pointing to a GCS object via `/vsigs/` path (e.g., `/vsigs/bucket-name/file.tif`)
2. Ensure `GOOGLE_APPLICATION_CREDENTIALS` is set and valid with GCS read permissions
3. Request the coverage without a bbox parameter: GET /collections/raster_collection/coverage?format=tif

4. Observe error:FileNotFoundError: [Errno 2] No such file or directory: '/vsigs/bucket-name/file.tif'

5. Request the same coverage *with* a bbox parameter: GET /collections/raster_collection/coverage?bbox=3.0,56.5,32.0,71.5&format=tif

6. Observe the request succeeds and returns the raster data

## Expected Behavior

Coverage requests should handle GDAL VSI paths correctly regardless of whether optional parameters like `bbox` are present. Both requests should succeed when the credentials and path are valid.

## Environment

- **pygeoapi version:** 0.24.0
- **Python version:** 3.11 (in geopython/pygeoapi:0.24.0 base image)
- **Operating System:** Windows 10/11 (Docker Desktop)
- **GDAL/rasterio version:** Latest in base image (rasterio 1.3.x+)
- **Storage backend:** Google Cloud Storage (GCS) via `/vsigs/` VSI path

Start with the rasterio coverage provider's early-return path and util.read_data(), then reproduce the coverage request with a /vsigs/ path both with and without bbox. Check the existing rasterio/provider tests for the closest coverage request cases. Done means native-format requests without bbox handle VSI paths and the existing bbox behavior remains successful.

Written by the indexing model from the issue text.