+ client: Display upstreams list loaded from a file

Squashed commit of the following:

commit b5abc9115806f345c8d0dd5ea00b8552d27813f9
Merge: 92708411 c1c8abdd
Author: ArtemBaskal <a.baskal@adguard.com>
Date:   Mon Sep 7 14:38:06 2020 +0300

    Merge branch '1680-upstreams-file' into feature/1680

commit 92708411f07638c037e049ee8012d15bdeda77e4
Author: ArtemBaskal <a.baskal@adguard.com>
Date:   Fri Sep 4 13:54:24 2020 +0300

    + client: Display upstreams list loaded from a file

client/src/components/Settings/Dns/Upstream/index.js

@@ -12,15 +12,28 @@ const Upstream = () => {
         upstream_dns,
         bootstrap_dns,
         upstream_mode,
-        processingSetConfig,
     } = useSelector((state) => state.dnsConfig, shallowEqual);
 
-    const { processingTestUpstream } = useSelector((state) => state.settings, shallowEqual);
+    const upstream_dns_file = useSelector((state) => state.dnsConfig.upstream_dns_file);
 
     const handleSubmit = (values) => {
-        dispatch(setDnsConfig(values));
+        const {
+            bootstrap_dns,
+            upstream_dns,
+            upstream_mode,
+        } = values;
+
+        const dnsConfig = {
+            bootstrap_dns,
+            upstream_mode,
+            ...(upstream_dns_file ? null : { upstream_dns }),
+        };
+
+        dispatch(setDnsConfig(dnsConfig));
     };
 
+    const upstreamDns = upstream_dns_file ? t('configured_in', { path: upstream_dns_file }) : upstream_dns;
+
     return <Card
         title={t('upstream_dns')}
         subtitle={t('upstream_dns_hint')}
@@ -30,13 +43,11 @@ const Upstream = () => {
             <div className="col">
                 <Form
                     initialValues={{
-                        upstream_dns,
+                        upstream_dns: upstreamDns,
                         bootstrap_dns,
                         upstream_mode,
                     }}
                     onSubmit={handleSubmit}
-                    processingTestUpstream={processingTestUpstream}
-                    processingSetConfig={processingSetConfig}
                 />
             </div>
         </div>