Collapse runs of deleted messages in the timeline (#7195)

* Collapse runs of deleted messages in the timeline (#7111)

* Collapse runs of deleted messages in the timeline

Collapse a run of three or more consecutive deleted messages into a single
expandable group, reusing the existing state-change grouping (the same way
element-web does it) instead of showing one "Message removed" placeholder per
deletion. The header shows the count only ("N deleted messages"); the Rust SDK
does not expose who performed the redaction, so we don't attribute it.

On by default. Runs shorter than three are left as individual placeholders, and
day dividers and read receipts are preserved (a run is broken by any
non-redacted item, so a day is never emptied).

Run the collapse as the final step of TimelineItemGrouper.group() instead of
a separate pass in the presenter, as suggested in review. Kept as its own
finalization step rather than via canBeGrouped() so the group stays all
redacted and the count-only header is preserved.
The group id is resolved through the grouper's existing id registry, like the
other groups, so it stays stable however the run grows and the user's
expand/collapse state is kept across timeline updates.

* Replace temporary strings with final ones

* Update screenshots

---------

Co-authored-by: Hi Dude! <klarkmonty@tuta.io>
Co-authored-by: manfrommedan <manfrommedan@users.noreply.github.com>
Co-authored-by: ElementBot <android@element.io>

tests/konsist/src/test/kotlin/io/element/android/tests/konsist/KonsistPreviewTest.kt

@@ -158,6 +158,7 @@ class KonsistPreviewTest {
         "TimelineItemGroupedEventsRowContentCollapsePreview",
         "TimelineItemGroupedEventsRowContentExpandedPreview",
         "TimelineItemImageViewHideMediaContentPreview",
+        "TimelineItemRedactedMessagesGroupPreview",
         "TimelineItemVideoViewHideMediaContentPreview",
         "TimelineItemVoiceViewUnifiedPreview",
         "TimelineVideoWithCaptionRowPreview",

tests/uitests/src/test/snapshots/images/features.preferences.impl.userstatus_UserStatusView_Day_5_en.png

@@ -1,3 +1,3 @@
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+size 12115

tests/uitests/src/test/snapshots/images/features.preferences.impl.userstatus_UserStatusView_Day_6_en.png

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+size 12013

tests/uitests/src/test/snapshots/images/features.preferences.impl.userstatus_UserStatusView_Night_5_en.png

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tests/uitests/src/test/snapshots/images/features.preferences.impl.userstatus_UserStatusView_Night_6_en.png

@@ -1,3 +1,3 @@
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