ForumPosts: Add spacing between TrustIndicator and timestamp

While trying to fix #421, I've at least added this spacing between TrustIndicator and the timestamp to prevent them from being glued together.

briar-desktop/src/main/kotlin/org/briarproject/briar/desktop/forums/ThreadItemView.kt

@@ -121,6 +121,7 @@ fun ThreadItemContentComposable(
         ) {
             Row(
                 modifier = Modifier.fillMaxWidth(),
+                horizontalArrangement = spacedBy(8.dp),
             ) {
                 Row(
                     modifier = Modifier.weight(1f),