[P2][HR][Gaps][Navigation][Test] Add regression test for modifying VM constructor body logic

[kazo0]

Source

Sub-issue of unoplatform/private#926. Tracked from the HR + Navigation test matrix.

Status from matrix

Works — verified during the manual HR pass against the Chefs sample.

Scenario

Editing the constructor body logic of a nav-target VM (e.g. how Recipe or SearchFilter is used inside RecipeDetailsModel / SearchModel) and applying HR. The pages remain functional and navigation reaches the updated logic.

Goal

This scenario was reported as working under HR. To prevent future regressions, we need a Hot Reload regression test in the Uno.Extensions HR testharness that exercises this exact scenario by triggering the relevant edits at runtime and asserting expected post-HR behavior.

Acceptance

• Regression test added in the HR testharness covering: Modify a navigation target VM constructor body logic and assert HR + navigation still work
• Test runs as part of CI on the relevant platforms