Add ability to mock out the azure query result in the unit test suite

[ytsarev]

Description of your changes

• Ability to mock out az resource graph query result to enable proper testing on unit level
• Refactor to smaller internal functions
• Add associated test case for query result to XR status propagation

Tests

• Unit

go test -v -cover .
=== RUN   TestRunFunction
=== RUN   TestRunFunction/ResponseIsReturned
=== RUN   TestRunFunction/ResponseIsReturnedWithOptionalManagementGroups
=== RUN   TestRunFunction/ShouldUpdateXRStatus
--- PASS: TestRunFunction (0.00s)
    --- PASS: TestRunFunction/ResponseIsReturned (0.00s)
    --- PASS: TestRunFunction/ResponseIsReturnedWithOptionalManagementGroups (0.00s)
    --- PASS: TestRunFunction/ShouldUpdateXRStatus (0.00s)
PASS
coverage: 44.6% of statements
ok  	github.com/upboundcare/function-azresourcegraph	(cached)	coverage: 44.6% of statements

• Integration with running function in dev mode

go run . --insecure --debug

crossplane render example/xr.yaml example/composition.yaml example/functions-dev.yaml --function-credentials=example/secrets/azure-creds-real.yaml -r
---
apiVersion: example.crossplane.io/v1
kind: XR
metadata:
  name: example-xr
status:
  azResourceGraphQueryResult:
  - id: /subscriptions/<redacted>/resourceGroups/us-vm-zxqnj-
  conditions:
  - lastTransitionTime: "2024-01-01T00:00:00Z"
    reason: Available
    status: "True"
    type: Ready
---
apiVersion: render.crossplane.io/v1beta1
kind: Result
message: 'Query: "Resources | project name, location, type, id| where type =~ ''Microsoft.Compute/virtualMachines''
  | order by name desc"'
severity: SEVERITY_NORMAL
step: query-azresourcegraph

I have:

• Read and followed Crossplane's contribution process.
• Added or updated unit tests for my change.

[kaessert]

lgtm