msglist: Update chevron design in StreamMessageRecipientHeader

Switch from colored background with chevron shaped border
to inline chevron icon. Also reset font and color styling
from headers, but subsequent commits will reintroduce
these to match the updated design.

Author: sirpengi

lib/widgets/message_list.dart

@@ -549,23 +549,23 @@ class StreamMessageRecipientHeader extends StatelessWidget {
     final stream = store.streams[message.streamId];
     final topic = message.subject;
 
-    final subscription = store.subscriptions[message.streamId];
-    final streamColor = Color(subscription?.color ?? 0x00c2c2c2);
-    final contrastingColor =
-      ThemeData.estimateBrightnessForColor(streamColor) == Brightness.dark
-        ? Colors.white
-        : Colors.black;
-
     final streamWidget = (showStream)
       ? GestureDetector(
           onTap: () => Navigator.push(context,
             MessageListPage.buildRoute(context: context,
               narrow: StreamNarrow(message.streamId))),
-          child: RecipientHeaderChevronContainer(
-            color: streamColor,
+          child: Row(children: [
+            const SizedBox(width: 16),
             // TODO globe/lock icons for web-public and private streams
-            child: Text(stream?.name ?? message.displayRecipient, // TODO(log) if missing
-              style: TextStyle(color: contrastingColor))))
+            Text(stream?.name ?? message.displayRecipient), // TODO(log) if missing
+            Padding(
+              // Figma has 5px horizontal padding around an 8px wide icon.
+              // Icon is 16px wide here so horizontal padding is 1px.
+              padding: const EdgeInsets.symmetric(horizontal: 1),
+              child: Icon(size: 16,
+                color: const HSLColor.fromAHSL(0.60, 0, 0, 0).toColor(),
+                ZulipIcons.chevron_right)),
+          ]))
       : const SizedBox(width: 16);
 
     return GestureDetector(
@@ -584,8 +584,7 @@ class StreamMessageRecipientHeader extends StatelessWidget {
               child: Text(topic,
                 // TODO: Give a way to see the whole topic (maybe a
                 //   long-press interaction?)
-                overflow: TextOverflow.ellipsis,
-                style: const TextStyle(fontWeight: FontWeight.w600)))),
+                overflow: TextOverflow.ellipsis))),
           // TODO topic links?
           // Then web also has edit/resolve/mute buttons. Skip those for mobile.
           RecipientHeaderDate(message: message,