Description of problem:
When trying to query a CR that was created from a plugin (like Azure or Google) via GraphQL, an error occurs.

Version-Release number of selected component (if applicable):
6.13.0, but should happen on any other too

How reproducible:
100%

Steps to Reproduce:
1. create an Azure (or in 6.13 Google) CR
2. curl -X POST -H "Content-Type: application/json" -d '{"query": "

{ computeResource(id: \"MDE6Rm9yZW1hbkF6dXJlUm06OkF6dXJlUm0tMTI=\") \{id, provider\} }

"}' -u admin:changeme https://$(hostname -f)/api/graphql (replace the ID with the right for your install

Actual results:

{"error":"An error occurred."}

Expected results:

{"data":"computeResource":"id":"MDE6Rm9yZW1hbkF6dXJlUm06OkF6dXJlUm0tMTI=","provider":"AzureRm"}

}}

Additional info:
In production log, we see the following error:
2023-05-09T06:43:41 [W|app|02510a9d] Action failed
2023-05-09T06:43:41 [I|app|02510a9d] Backtrace for 'Action failed' error (Types::ProviderEnum::UnresolvedValueError): `ComputeResource.provider` returned `"AzureRm"` at `computeResource.provider`, but this isn't a valid value for `
ProviderEnum`. Update the field or resolver to return one of `ProviderEnum`'s values instead.
02510a9d | /usr/share/gems/gems/graphql-1.13.16/lib/graphql/schema/enum.rb:161:in `coerce_result'

This is because app/graphql/types/provider_enum.rb uses `supported_providers` and not `all_providers` to obtain the list of providers.

irb(main):001:0> ::ComputeResource.supported_providers.keys
=> ["Libvirt", "Ovirt", "EC2", "Vmware", "Openstack"]
irb(main):002:0> ::ComputeResource.all_providers.keys
=> ["Libvirt", "Ovirt", "EC2", "Vmware", "Openstack", "AzureRm", "GCE"]