Add Inter 600, fix ChatPaneHeader font weight

app/soapbox/features/chats/components/chat-widget/chat-pane-header.tsx

@@ -37,11 +37,9 @@ const ChatPaneHeader = (props: IChatPaneHeader) => {
         data-testid='title'
         {...buttonProps}
       >
-        {typeof title === 'string' ? (
-          <Text weight='semibold'>
-            {title}
-          </Text>
-        ) : (title)}
+        <Text weight='semibold' tag='div'>
+          {title}
+        </Text>
 
         {(typeof unreadCount !== 'undefined' && unreadCount > 0) && (
           <HStack alignItems='center' space={2}>

app/styles/application.scss

@@ -4,6 +4,7 @@
 @import '~@fontsource/inter/300.css';
 @import '~@fontsource/inter/400.css';
 @import '~@fontsource/inter/500.css';
+@import '~@fontsource/inter/600.css';
 @import '~@fontsource/inter/700.css';
 @import '~@fontsource/inter/900.css';