TPT-4576: add 'When' field to AccountMaintenance struct

[zliang-akamai]

📝 Description

Add When back in AccountMaintenance.

✔️ How to Test

Unit testing only, see CI for the result.

[Copilot]

Pull request overview

This PR reintroduces the When timestamp on AccountMaintenance responses, ensuring the client can parse the API’s when field and that unit fixtures/tests validate the behavior.

Changes:

• Added When *time.Time to AccountMaintenance and wired it into the custom UnmarshalJSON.
• Updated the unit fixture JSON to include the when field for each maintenance record.
• Extended the unit test to assert When is present and correctly parsed.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
account_maintenance.go	Adds When and parses it from the API payload via parseabletime.
test/unit/fixtures/account_maintenance_list.json	Adds when values to fixture data used by unit tests.
test/unit/account_maintenance_test.go	Validates When is unmarshaled and matches expected RFC3339 timestamps.

Comments suppressed due to low confidence (1)

test/unit/account_maintenance_test.go:58

• assert.NotNil does not stop the test, so maintenances[1].When.Format(...) can still panic if When is nil. Guard the Format call (or switch to require.NotNil).

	assert.NotNil(t, maintenances[1].When)
	assert.Equal(t, "2025-03-25T11:00:00Z", maintenances[1].When.Format(time.RFC3339))

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.