Push remaining PureReportActionItem subscriptions into leaf components

[cristipaval]

Problem

After the branch extractions from #87157, a plain ADD_COMMENT report action cell still carries 22 Onyx subscriptions at the PureReportActionItem level — many of which are only consumed by specialty branches (approval flows, whispers, trip previews, etc.).

Proposed fix

Move 6 remaining subscriptions (reportMetadata, personalPolicyID, parentReport, childReport, policy, CONCIERGE_REPORT_ID) from PureReportActionItem into the leaf components that actually use them. Extract WhisperBanner and SearchActionHeader as self-gating components.

Target: 22 → 16 subscriptions per plain ADD_COMMENT cell (~770 fewer subscriptions for a typical 87-item list).

POC: #89107

Issue Owner

Current Issue Owner: @LukasMod

[LukasMod]

• PR 1: push down 5 wrapper subscriptions into action leaves. Draft PR: refactor: PureReportActionItem, push down 5 wrapper subscriptions into action leaves #89160
• PR 2: extract WhisperBanner and SearchActionHeader. Draft PR: refactor: PureReportActionItem, extract WhisperBanner and SearchActionHeader #89169

I will work on preparing test videos for these now and I found few small ideas around this component:

• derive moderationDecision from action, drop redundant useState
• decompose ReportActionItemSingle useOnyx(PERSONAL_DETAILS_LIST) into two self-gated leaves (-1 sub for most of cases when we are not grouping)
• move composer focus and deleted-draft cleanup into ReportActionItemMessageEdit (-1 useRef, -2 useEffect)
• move the SearchStateContext consumer for currentSearchHash into ChatMessageContent
• reduce prop drilling on PureReportActionItem (resolveActionableReportMentionWhisper, resolveActionableMentionWhisper, isCurrentUserTheOnlyParticipant, deleteReportActionDraft, clearError, clearAllRelatedReportActionErrors, getTransactionsWithReceipts)
• investigate MiniReportActionContextMenu lazy rendering
• extract the inline render helpers into real components (renderItemContent, itemContent, renderReportActionItem, createdActionContent)

[cristipaval]

Thanks @LukasMod! I've created 2 subissues for your draft PRs.

[LukasMod]

I rebased these 2 first PRs so these no longer need to wait for the last one in review. Both ready for review now.
Working on next sub-issue PRs. I’ll be OOO on 1.05 due to the bank holiday.

[LukasMod]

PR 3: drop moderation state and prop drilling: #89468 (waiting to link sub-issue)

Working on next one