Use az group exists instead of az group show for resource group existence checks

[Copilot]

does_resource_group_exist was relying on az group show returning an error to infer a group doesn't exist — basing control flow on error conditions rather than clean boolean output.

Changes

• shared/python/azure_resources.py: Switch does_resource_group_exist to az group exists, which returns true/false without errors.

# Before
output = run(f'az group show --name {resource_group_name} -o json')
return output.success

# After
output = run(f'az group exists --name {resource_group_name}')
return output.success and output.text.strip().lower() == 'true'

• tests/python/test_azure_resources.py: Updated tests to reflect the new command and output format. Notably, az group exists always exits cleanly (exit code 0) — existence is determined by the true/false text output, not the return code.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[Bug]: Use az group exists instead of az group show when checking whether group exists</issue_title>
<issue_description>### Describe the bug

Consider using az group exists instead of az group show when we check for the presence of a resource group (before creation, etc.). The latter returns an error when the resource group doesn't exist. While this has worked, we should not base logic on errors.

To Reproduce

Run an infrastructure creation with the log level on DEBUG to see it.

Expected behavior

Not base logic on an error.

Screenshots

No response

CPU Architecture

None

Other CPU Architecture

No response

Operating System

None

Other Operating System

No response</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [Bug]: Use az group exists instead of az group show when checking whether group exists #156

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[github-actions]

🐍 Python 3.14 Results

Metric	Status	Value
Ruff	✅	0 issue(s)
Unit Tests	✅	success
Code Coverage	📊	100%

Full Workflow Logs

[github-actions]

Python 3.14 Detailed Test Results

1 562 tests  +1   1 562 ✅ +1   11s ⏱️ -4s
    1 suites ±0       0 💤 ±0 
    1 files   ±0       0 ❌ ±0 

Results for commit 0d08d5f. ± Comparison against base commit ae7fd7d.

♻️ This comment has been updated with latest results.

[github-actions]

🐍 Python 3.12 Results

Metric	Status	Value
Ruff	✅	0 issue(s)
Unit Tests	✅	success
Code Coverage	📊	100%

Full Workflow Logs

[github-actions]

🐍 Python 3.13 Results

Metric	Status	Value
Ruff	✅	0 issue(s)
Unit Tests	✅	success
Code Coverage	📊	100%

Full Workflow Logs

[github-actions]

Python 3.12 Detailed Test Results

1 562 tests  +1   1 562 ✅ +1   16s ⏱️ -1s
    1 suites ±0       0 💤 ±0 
    1 files   ±0       0 ❌ ±0 

Results for commit 0d08d5f. ± Comparison against base commit ae7fd7d.

♻️ This comment has been updated with latest results.

[github-actions]

Python 3.13 Detailed Test Results

1 562 tests  +1   1 562 ✅ +1   15s ⏱️ ±0s
    1 suites ±0       0 💤 ±0 
    1 files   ±0       0 ❌ ±0 

Results for commit 0d08d5f. ± Comparison against base commit ae7fd7d.

♻️ This comment has been updated with latest results.