[Due for payment 2026-07-08] [Odometer] Show discard changes modal when switching tabs with unsaved values

[Julesssss]

Problem

When a user has filled in values in the odometer flow and switches tabs without saving, the values are lost without warning. This is inconsistent with the existing close-flow behavior, which shows a discard confirmation modal when users click outside to close.

Solution

Display the discard changes confirmation modal when the user switches tabs with unsaved filled-in values, matching the existing close-flow behavior.

WIP PR: #89612

Issue Owner

Current Issue Owner: @mallenexpensify

[Julesssss]

PR was blocked, now underway again

[jakubkalinski0]

Still holding PR on #90445 -> good progress being done there

[jakubkalinski0]

We are close to getting #90445 merged. After that, work on this issue will be resumed

[Julesssss]

#90445 merged 🎉