Advance read receipts into trailing events without tiles

This changes read receipt sending logic to allow it advance further into events
without tiles (such as edits or reactions) that may exist after the last
displayed event.

By allowing the read receipt to advance past such events, this also marks as
read any related notifications. For example, edits trigger notifications by
default since they are `m.room.message` events, and with this change, such edit
notifications can finally be marked read.

Part of https://github.com/vector-im/riot-web/issues/9745

src/shouldHideEvent.js

@@ -45,6 +45,8 @@ export default function shouldHideEvent(ev) {
 
     // Hide redacted events
     if (ev.isRedacted() && !isEnabled('showRedactions')) return true;
+
+    // Hide replacement events since they update the original tile
     if (ev.isRelation("m.replace")) return true;
 
     const eventDiff = memberEventDiff(ev);