Use the theme colour for the file icon in the SIMPLEX chat list

A chat whose last message is a file showed the file icon in the chat
wallpaper's warm tint, so it turned yellow under the "cats" wallpaper.
In the chat list the icon should match the neighbouring list icons, so
on SIMPLEX it now uses the theme's secondary colour there; inside the
chat, over the gradient, the icon keeps the warm tint.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/views/chat/item/CIFileView.kt

@@ -59,7 +59,7 @@ fun CIFileView(
         painterResource(MR.images.ic_draft_filled),
         stringResource(MR.strings.icon_descr_file),
         Modifier.fillMaxSize(),
-        tint = if (isSimplex && isDefaultTint) simplexSecondaryTint() else color
+        tint = if (isSimplex && isDefaultTint) { if (smallView) MaterialTheme.colors.secondary else simplexSecondaryTint() } else color
       )
       if (innerIcon != null) {
         Icon(