Refactor(NoteList): Use already assigned list iterator

In the existing code we're recomputing the current list item in the note list
when we've already assigned it above. In this patch we're using the
already-assigned value.

This is part of broader work to separate modifying the search parameters from
actually filtering the notes and was originally created as part of an
exploratory PR #1807.

RELEASE-NOTES.txt

@@ -25,7 +25,7 @@
 - Added React Hooks ESLint Plugin [#1789](https://github.com/Automattic/simplenote-electron/pull/1789)
 - Added end-to-end testing with Spectron [#1773](https://github.com/Automattic/simplenote-electron/pull/1773)
 - Removed a workaround for indexing note pinned status [#1795](https://github.com/Automattic/simplenote-electron/pull/1795)
-- Maintenance cleanups [#1796](https://github.com/Automattic/simplenote-electron/pull/1796), [#1797](https://github.com/Automattic/simplenote-electron/pull/1797)
+- Maintenance cleanups [#1796](https://github.com/Automattic/simplenote-electron/pull/1796), [#1797](https://github.com/Automattic/simplenote-electron/pull/1797), [#1808](https://github.com/Automattic/simplenote-electron/pull/1808)
 - Updated dependencies [#1802](https://github.com/Automattic/simplenote-electron/pull/1802)
 
 ## [v1.13.0]

lib/note-list/index.jsx

@@ -126,7 +126,7 @@ const rowHeightCache = f => (
 
   const { preview } = getNoteTitleAndPreview(note);
 
-  const key = notes[index].id;
+  const key = note.id;
   const cached = previewCache.get(key);
 
   if ('undefined' !== typeof cached) {