LibConfig+ConfigServer: Write config values synchronously

This patch fixes the issue of pressing the ok button of a settings menu
without saving the changes, or not reverting the changes when pressing
the cancel button because the app has died before the new values make
it to the other end.

Userland/Libraries/LibConfig/Client.cpp

@@ -57,17 +57,17 @@ bool Client::read_bool(StringView domain, StringView group, StringView key, bool
 
 void Client::write_string(StringView domain, StringView group, StringView key, StringView value)
 {
-    async_write_string_value(domain, group, key, value);
+    write_string_value(domain, group, key, value);
 }
 
 void Client::write_i32(StringView domain, StringView group, StringView key, i32 value)
 {
-    async_write_i32_value(domain, group, key, value);
+    write_i32_value(domain, group, key, value);
 }
 
 void Client::write_bool(StringView domain, StringView group, StringView key, bool value)
 {
-    async_write_bool_value(domain, group, key, value);
+    write_bool_value(domain, group, key, value);
 }
 
 void Client::remove_key(StringView domain, StringView group, StringView key)

Userland/Services/ConfigServer/ConfigServer.ipc

@@ -11,8 +11,8 @@ endpoint ConfigServer
     read_i32_value(String domain, String group, String key) => (Optional<i32> value)
     read_bool_value(String domain, String group, String key) => (Optional<bool> value)
 
-    write_string_value(String domain, String group, String key, String value) =|
-    write_i32_value(String domain, String group, String key, i32 value) =|
-    write_bool_value(String domain, String group, String key, bool value)  =|
+    write_string_value(String domain, String group, String key, String value) => ()
+    write_i32_value(String domain, String group, String key, i32 value) => ()
+    write_bool_value(String domain, String group, String key, bool value)  => ()
     remove_key(String domain, String group, String key) =|
 }