refactor: replace okhttp3.internal.closeQuietly with local extension

okhttp3.internal.closeQuietly is an unstable internal API that could be
removed in a future OkHttp patch without deprecation. Replace it with a
small private Closeable.closeQuietly() extension (same semantics) so the
OkHttp upgrade path stays robust.

Author: hawkff

app/src/main/java/io/nekohasekai/sagernet/ui/ConfigurationFragment.kt

@@ -116,7 +116,7 @@ import moe.matsuri.nb4a.proxy.anytls.AnyTLSSettingsActivity
 import moe.matsuri.nb4a.proxy.config.ConfigSettingActivity
 import moe.matsuri.nb4a.proxy.shadowtls.ShadowTLSSettingsActivity
 import moe.matsuri.nb4a.ui.ConnectionTestNotification
-import okhttp3.internal.closeQuietly
+import java.io.Closeable
 import java.net.InetSocketAddress
 import java.net.Socket
 import java.net.UnknownHostException
@@ -2052,3 +2052,14 @@ class ConfigurationFragment @JvmOverloads constructor(
     }
 
 }
+
+/**
+ * Closes this resource, ignoring any exception. Replacement for OkHttp's internal
+ * `closeQuietly()` extension so we don't depend on an unstable `okhttp3.internal` API.
+ */
+private fun Closeable.closeQuietly() {
+    try {
+        close()
+    } catch (_: Exception) {
+    }
+}