Fixes a rasterio query using format=json and a MemoryFile issue

[Alex-NRCan]

Overview

There is an issue when writing the raster data with the MemoryFile.
The issue is present in the demo and can be tested easily with a query such as this one:
https://demo.pygeoapi.io/master/collections/gdps-temperature/coverage?f=json&lang=en-US&bbox=-118,52,-116,54

This fix (more an optimization) changes the code to not work with a MemoryFile at all (doesn't need to) when the queried format is json.

Note, the MemoryFile is still being used when format isn't json.

Related Issue / discussion

Additional information

Dependency policy (RFC2)

• I have ensured that this PR meets RFC2 requirements

Updates to public demo

• I have ensured that breaking changes to the pygeoapi master demo server have been addressed
  • https://github.com/geopython/demo.pygeoapi.io/blob/master/services/pygeoapi_master/local.config.yml

Contributions and licensing

(as per https://github.com/geopython/pygeoapi/blob/master/CONTRIBUTING.md#contributions-and-licensing)

• I'd like to contribute [feature X|bugfix Y|docs|something else] to pygeoapi. I confirm that my contributions to pygeoapi will be compatible with the pygeoapi license guidelines at the time of contribution
• I have already previously agreed to the pygeoapi Contributions and Licensing Guidelines

[tomkralidis]

@Alex-NRCan thanks for this. Can you fill in/checkoff the appropriate areas in the pull request text?

[Alex-NRCan]

Ok, I think I checked off the boxes now 👍