Fix unread notification count in room list (#7749)

* Display the unread notification count only when needed

* Adjust `CounterAtom` and `UnreadIndicatorAtom` to use the official M3's `Badge` component, with a few tweaks to ensure single digit items are always displayed as a circle

* +99 is now 99+

* Update screenshots

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Co-authored-by: ElementBot <android@element.io>

libraries/matrixui/src/main/kotlin/io/element/android/libraries/matrix/ui/model/InviteSender.kt

@@ -9,6 +9,7 @@
 package io.element.android.libraries.matrix.ui.model
 
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.Immutable
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.AnnotatedString
 import androidx.compose.ui.text.SpanStyle
@@ -20,6 +21,7 @@ import io.element.android.libraries.matrix.api.core.UserId
 import io.element.android.libraries.matrix.api.room.RoomMember
 import io.element.android.libraries.matrix.ui.R
 
+@Immutable
 data class InviteSender(
     val userId: UserId,
     val displayName: String,