fix(http sink): cert verification with proxy enabled (#13759)

Author: ntim

src/http.rs

@@ -139,8 +139,15 @@ pub fn build_proxy_connector(
     tls_settings: MaybeTlsSettings,
     proxy_config: &ProxyConfig,
 ) -> Result<ProxyConnector<HttpsConnector<HttpConnector>>, HttpError> {
+    // Create dedicated TLS connector for the proxied connection with user TLS settings.
+    let tls = tls_connector_builder(&tls_settings)
+        .context(BuildTlsConnectorSnafu)?
+        .build();
     let https = build_tls_connector(tls_settings)?;
     let mut proxy = ProxyConnector::new(https).unwrap();
+    // Make proxy connector aware of user TLS settings by setting the TLS connector:
+    // https://github.com/vectordotdev/vector/issues/13683
+    proxy.set_tls(Some(tls));
     proxy_config
         .configure(&mut proxy)
         .context(MakeProxyConnectorSnafu)?;