Engg. Hygiene: Introduce Extension Status Asserter and use in example Test class

[kjohn-msft]

Test harness improvement to allow unit tests to deterministically check extension status.

In this PR:

1. Addresses issues like widely broken tests if order of entries in the extension status output changes. Indexing is by name, not by order (so no brittle hardcoding).
2. Has performant one-time memory load and evaluation.
3. Assert mechanics:

• Status validation - assert_status_file_substatus(operation, expected_status)
• Batch status validation - assert_status_file_substatuses()
• Patch-level validation - assert_operation_summary_has_patch(...)
• Error validation - assert_operation_summary_has_error(...)
• Metadata validations - assert_operation_summary_has_started_by(), assert_configure_patching_patch_mode_state(), assert_configure_patching_auto_assessment_state(), assert_healthstore_status_info()
  - Extensible beyond this

4. Applies all this into the ConfigurePatching unit test flow.

• This exercise revealed that a test written for auto-assessment for Arc wasn't guarding against everything it could guard against. I'm leaving that out of the scope of this PR.

Future changes:
All code authors can rely on this for new tests.
Existing tests may be rewritten as a new-hire exercise.

(Note: This was previously bundled into the commit history of https://github.com/Azure/LinuxPatchExtension/pull/313/changes - moved it out separately as good practice)

[Copilot]

Pull request overview

This PR introduces a reusable ExtStatusAsserter helper for unit tests to validate extension status/substatus output by substatus name (not array position), and updates the ConfigurePatching processor tests to use these deterministic assertions instead of brittle index-based checks.

Changes:

• Added ExtStatusAsserter test utility to load the status file once and provide higher-level assertion helpers (substatus, errors, patch presence, metadata).
• Refactored portions of Test_ConfigurePatchingProcessor to use the new asserter rather than hard-coded substatus ordering.
• Minor logging/documentation tweaks in core logic (ConfigurePatchingProcessor, ServiceManager).

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 7 comments.

File	Description
src/core/tests/Test_ConfigurePatchingProcessor.py	Replaces index-based status-file assertions with ExtStatusAsserter calls in several tests.
src/core/tests/library/ExtStatusAsserter.py	New helper implementing status/substatus parsing and assertion APIs for tests.
src/core/src/core_logic/ServiceManager.py	Adds a short docstring to remove_service().
src/core/src/core_logic/ConfigurePatchingProcessor.py	Adds log prefixes/verbose logs and introduces a cleanup helper method (currently unused).

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[codecov]

Codecov Report

❌ Patch coverage is 99.58848% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 94.06%. Comparing base (ba18a31) to head (c95b305).

Files with missing lines	Patch %	Lines
src/core/tests/Test_ExtStatusAsserter.py	99.09%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #352      +/-   ##
==========================================
+ Coverage   94.01%   94.06%   +0.04%     
==========================================
  Files         107      109       +2     
  Lines       19686    19840     +154     
==========================================
+ Hits        18508    18662     +154     
  Misses       1178     1178              

Flag	Coverage Δ
python27	94.06% <99.58%> (+0.04%)	⬆️
python312	94.02% <99.58%> (+<0.01%)	⬆️

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