Room topic: tweak collapse behaviour some more

One could argue that collapsing is only useful if we have more than 2
lines to hide.
Also, @su-ex wants more lines, so let's go for 5+3.

Change-Id: I5f3580171d4b1544fd8f91f1de48cea85023b60a

vector/src/main/java/im/vector/app/core/epoxy/ExpandableTextItem.kt

@@ -36,6 +36,10 @@ abstract class ExpandableTextItem : VectorEpoxyModel<ExpandableTextItem.Holder>(
     @EpoxyAttribute
     var maxLines: Int = 3
 
+    // Number of hidden lines that justify collapsing
+    @EpoxyAttribute
+    var minCollapsedLines: Int = 2
+
     private var isExpanded = false
     private var expandedLines = 0
 
@@ -47,7 +51,7 @@ abstract class ExpandableTextItem : VectorEpoxyModel<ExpandableTextItem.Holder>(
         holder.content.doOnPreDraw {
             // Allow for displaying maxLines + 1 lines: in this case, the expand button
             // would reserve just as much space as the expaned text
-            if (holder.content.lineCount > maxLines + 1) {
+            if (holder.content.lineCount > maxLines + minCollapsedLines) {
                 expandedLines = holder.content.lineCount
                 holder.content.maxLines = maxLines
 
@@ -61,7 +65,7 @@ abstract class ExpandableTextItem : VectorEpoxyModel<ExpandableTextItem.Holder>(
                 holder.arrow.isVisible = true
             } else {
                 holder.arrow.isVisible = false
-                holder.content.maxLines = maxLines + 1
+                holder.content.maxLines = maxLines + minCollapsedLines
             }
         }
     }

vector/src/main/java/im/vector/app/features/roomprofile/RoomProfileController.kt

@@ -68,7 +68,8 @@ class RoomProfileController @Inject constructor(
                     expandableTextItem {
                         id("topic")
                         content(it)
-                        maxLines(3)
+                        maxLines(5)
+                        minCollapsedLines(3)
                     }
                 }