enzyme -> RTL: convert the InstanceGroup screen suites

[blaipr]

SUMMARY

Converts the InstanceGroup screen's test suite from enzyme to React Testing Library, continuing the incremental enzyme → RTL migration (one screen directory per PR).

Files migrated off mountWithContexts/enzyme onto renderWithContexts:

• InstanceGroup + ContainerGroup Add / Edit (shared forms mocked) and their Forms (pod-spec editor label asserted, not YAML text)
• InstanceGroup + ContainerGroup Details — fields, delete (related-count reads mocked) + error
• InstanceGroupList / InstanceGroupListItem — load, selection, bulk delete enable/disable
• Instances sublist (InstanceList / InstanceListItem, InstanceDetails) — capacity/forks sliders (keyboard), enable toggle, API updates

Interactions now go through accessible roles and real user events. Behaviour and assertions are preserved.

ISSUE TYPE

• Bug, Docs Fix or other nominal change

COMPONENT NAME

• UI

ADDITIONAL INFORMATION

npm test for the InstanceGroup directory: 17 suites, 81 tests, all passing. ESLint clean. No production code changed — test-only.

A couple of enzyme-only no-op assertions (wrapper.length === 1, duplicate hidden-button cases) were folded into stronger behavioural checks, and one mislabeled list test was renamed to reflect the real mechanism (select-all disables Delete when a row lacks delete capability).

[Copilot]

Pull request overview

This PR continues the incremental UI test migration away from Enzyme by converting the InstanceGroup screen’s test suites to React Testing Library. It keeps coverage focused on user-visible behavior and accessibility-driven interactions while remaining test-only (no production code changes).

Changes:

• Replaced Enzyme mountWithContexts/act patterns with RTL renderWithContexts, screen, and real user events.
• Updated assertions to prefer accessible roles/names and behavior-based checks (e.g., modal open/close, button enable/disable, API calls).
• Improved isolation and async stability in several suites (fresh test objects, waitFor/findBy*, tooltip settling where needed).

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
awx/ui/src/screens/InstanceGroup/shared/InstanceGroupForm.test.js	Migrates the shared InstanceGroup form tests to RTL with user-event driven submit/cancel and field updates.
awx/ui/src/screens/InstanceGroup/shared/ContainerGroupForm.test.js	Converts ContainerGroup form tests to RTL, including async CredentialLookup behavior and pod-spec editor visibility.
awx/ui/src/screens/InstanceGroup/Instances/InstanceListItem.test.js	Migrates row rendering/expanded-row assertions and slider-driven capacity updates to RTL interactions.
awx/ui/src/screens/InstanceGroup/Instances/InstanceList.test.js	Converts Instances sublist suite to RTL, covering associate modal, selection-driven actions, and health check flows.
awx/ui/src/screens/InstanceGroup/InstanceGroupList/InstanceGroupListItem.test.js	Updates list item row assertions (type/capabilities/actions) to RTL queries via roles/cells.
awx/ui/src/screens/InstanceGroup/InstanceGroupList/InstanceGroupList.test.js	Migrates list suite to RTL, covering fetch/render, delete flows, protected rows disabling delete, and error states.
awx/ui/src/screens/InstanceGroup/InstanceGroupEdit/InstanceGroupEdit.test.js	Uses an RTL-friendly mocked shared form to directly drive edit submit/cancel handlers and verify navigation/API calls.
awx/ui/src/screens/InstanceGroup/InstanceGroupDetails/InstanceGroupDetails.test.js	Converts details suite to RTL, including DeleteButton confirmation flow with related-count reads mocked.
awx/ui/src/screens/InstanceGroup/InstanceGroupAdd/InstanceGroupAdd.test.js	Uses a mocked shared form under RTL to exercise create submit/cancel and submission error behavior.
awx/ui/src/screens/InstanceGroup/InstanceDetails/InstanceDetails.test.js	Migrates instance detail tests to RTL for health check/disassociate flows, capability gating, and error handling.
awx/ui/src/screens/InstanceGroup/ContainerGroupEdit/ContainerGroupEdit.test.js	Converts ContainerGroup edit suite to RTL with mocked shared form and options-fetch verification.
awx/ui/src/screens/InstanceGroup/ContainerGroupDetails/ContainerGroupDetails.test.js	Migrates ContainerGroup details tests to RTL, including credential link assertion and delete capability gating.
awx/ui/src/screens/InstanceGroup/ContainerGroupAdd/ContainerGroupAdd.test.js	Converts ContainerGroup add suite to RTL with mocked shared form and options-driven pod spec defaults.