[Due for payment 2026-07-13] [Split #88320] PR 11 - Simplify unread marker suppression rule

[rlinoz]

Goal: Remove prevUnreadMarkerReportActionID self-referential suppression and make unread marker behavior consistent.

Scope:

• Update useUnreadMarker.ts
• Update shouldDisplayNewMarkerOnReportAction.ts with behavior note
• Update MoneyRequestReportActionsList.tsx
• Add tests for own-message marker suppression

Risk: Low-medium. User-visible marker behavior changes.

Depends on: #89771

Parent issue: #88320
Source plan: #88320 (comment)

Issue Owner

Current Issue Owner: @DylanDylann

[melvin-bot]

This issue has not been updated in over 15 days. @rlinoz, @adhorodyski, @DylanDylann eroding to Monthly issue.

P.S. Is everyone reading this sure this is really a near-term priority? Be brave: if you disagree, go ahead and close it out. If someone disagrees, they'll reopen it, and if they don't: one less thing to do!

[LukasMod]

The original goal was to remove a prevUnreadMarkerReportActionID self-referential ref gate but it was already done in #91179. Recently it was reintroduced with proper useState pattern #91940 so original goal is stale.

Instead of the planned suppression-rule change, this PR implements the only simplification that's currently available: removing the now-dead report-change reset + unit tests. It's based on #93694, so I'll keep it as a draft until that PR is merged