Fix send attachment icon color (and remove useless Box)

libraries/textcomposer/src/main/kotlin/io/element/android/libraries/textcomposer/TextComposer.kt

@@ -316,13 +316,12 @@ private fun AttachmentButton(
     onClick: () -> Unit,
     modifier: Modifier = Modifier
 ) {
-    Box(modifier) {
     Surface(
-            Modifier
+        modifier
             .size(30.dp)
-                .clickable(true, onClick = onClick),
+            .clickable(onClick = onClick),
         shape = CircleShape,
-            color = MaterialTheme.colorScheme.primary
+        color = ElementTheme.colors.iconPrimary
     ) {
         Image(
             modifier = Modifier.size(12.5f.dp),
@@ -335,7 +334,6 @@ private fun AttachmentButton(
         )
     }
 }
-}
 
 @Composable
 private fun BoxScope.SendButton(