Only show a Matrix ID in the room picker for a direct message

heroes is populated for any room whose name is derived from its members,
not only for direct messages, so a two person room that is not a DM
showed a member's Matrix ID as its subtitle.

Carry isDm on SelectRoomInfo and read the hero only when it is set. The
canonical alias still takes precedence, so nothing changes for a room
that has one.

features/space/impl/src/main/kotlin/io/element/android/features/space/impl/addroom/AddRoomToSpaceStateProvider.kt

@@ -87,6 +87,7 @@ internal fun aSelectRoomInfoList(): ImmutableList<SelectRoomInfo> = listOf(
         canonicalAlias = null,
         avatarUrl = null,
         heroes = persistentListOf(),
+        isDm = false,
         isTombstoned = false,
     ),
     SelectRoomInfo(
@@ -95,6 +96,7 @@ internal fun aSelectRoomInfoList(): ImmutableList<SelectRoomInfo> = listOf(
         canonicalAlias = null,
         avatarUrl = null,
         heroes = persistentListOf(),
+        isDm = false,
         isTombstoned = false,
     ),
     SelectRoomInfo(
@@ -103,6 +105,7 @@ internal fun aSelectRoomInfoList(): ImmutableList<SelectRoomInfo> = listOf(
         canonicalAlias = null,
         avatarUrl = null,
         heroes = persistentListOf(),
+        isDm = false,
         isTombstoned = false,
     ),
 ).toImmutableList()