Properly map hashed legacy colors to the new color palette.

Fixes #8021

src/org/thoughtcrime/securesms/contacts/avatars/ContactColors.java

@@ -9,8 +9,31 @@ public class ContactColors {
 
   public static final MaterialColor UNKNOWN_COLOR = MaterialColor.GREY;
 
+  private static final String[] LEGACY_PALETTE = new String[] {
+      "red",
+      "pink",
+      "purple",
+      "deep_purple",
+      "indigo",
+      "blue",
+      "light_blue",
+      "cyan",
+      "teal",
+      "green",
+      "light_green",
+      "orange",
+      "deep_orange",
+      "amber",
+      "blue_grey"
+  };
+
   public static MaterialColor generateFor(@NonNull String name) {
-    return MaterialColors.CONVERSATION_PALETTE.get(Math.abs(name.hashCode()) % MaterialColors.CONVERSATION_PALETTE.size());
+    String serialized = LEGACY_PALETTE[Math.abs(name.hashCode()) % LEGACY_PALETTE.length];
+    try {
+      return MaterialColor.fromSerialized(serialized);
+    } catch (MaterialColor.UnknownColorException e) {
+      return MaterialColors.CONVERSATION_PALETTE.get(Math.abs(name.hashCode()) % MaterialColors.CONVERSATION_PALETTE.size());
+    }
   }
 
 }