feat: show if proxy is enabled in connectivity view (#7359)

closes #7269

src/stock_str.rs

@@ -436,6 +436,14 @@ https://delta.chat/donate"))]
         fallback = "The attachment contains anonymous usage statistics, which helps us improve Delta Chat. Thank you!"
     ))]
     StatsMsgBody = 210,
+
+    #[strum(props(fallback = "Proxy Enabled"))]
+    ProxyEnabled = 220,
+
+    #[strum(props(
+        fallback = "You are using a proxy. If you're having trouble connecting, try a different proxy."
+    ))]
+    ProxyEnabledDescription = 221,
 }
 
 impl StockMessage {
@@ -1309,6 +1317,16 @@ pub(crate) async fn backup_transfer_msg_body(context: &Context) -> String {
     translated(context, StockMessage::BackupTransferMsgBody).await
 }
 
+/// Stock string: `Proxy Enabled`.
+pub(crate) async fn proxy_enabled(context: &Context) -> String {
+    translated(context, StockMessage::ProxyEnabled).await
+}
+
+/// Stock string: `You are using a proxy. If you're having trouble connecting, try a different proxy.`.
+pub(crate) async fn proxy_description(context: &Context) -> String {
+    translated(context, StockMessage::ProxyEnabledDescription).await
+}
+
 impl Context {
     /// Set the stock string for the [StockMessage].
     ///