Improve test coverage in test_views.py

[glennmatthews]

Environment

• Nautobot version: 2.1.3
• nautobot-device-lifecycle-mgmt version: develop

Proposed Functionality

nautobot/nautobot#5254 caused several of the DLM list views to raise exceptions when accessed, however upstream CI test status for this App remained green / all tests passed. Looking at nautobot_device_lifecycle_mgmt/tests/test_views.py, a large number of tests are currently marked as @skip("not implemented"); my suspicion is that if these tests were implemented and enabled, they might have failed upstream CI tests due to the aforementioned issue and allowed us to catch it sooner, perhaps even before 2.1.3 was released.

Use Case

More comprehensive testing, earlier detection of fundamental breakage.