[netemul] Ensure logger doesn't run in unittests

- sandbox_unittests shouldn't need logger in environment. Removed it to
reduce resource usage during test runs.

BUG: CONN-123 #progress
Change-Id: Idb2336fff415d4b03e430b06a8c32ea5c91c3876
diff --git a/src/connectivity/network/testing/netemul/runner/model/config.cc b/src/connectivity/network/testing/netemul/runner/model/config.cc
index 54c2c61..f3e620b 100644
--- a/src/connectivity/network/testing/netemul/runner/model/config.cc
+++ b/src/connectivity/network/testing/netemul/runner/model/config.cc
@@ -116,6 +116,8 @@
 
 const Environment& Config::environment() const { return environment_; }
 
+Environment& Config::environment() { return environment_; }
+
 const std::string& Config::default_url() const { return default_url_; }
 
 bool Config::disabled() const { return disabled_; }
diff --git a/src/connectivity/network/testing/netemul/runner/model/config.h b/src/connectivity/network/testing/netemul/runner/model/config.h
index 17123c6..74d2937 100644
--- a/src/connectivity/network/testing/netemul/runner/model/config.h
+++ b/src/connectivity/network/testing/netemul/runner/model/config.h
@@ -30,6 +30,7 @@
 
   const std::vector<Network>& networks() const;
   const Environment& environment() const;
+  Environment& environment();
   const std::string& default_url() const;
   bool disabled() const;
   zx::duration timeout() const;
diff --git a/src/connectivity/network/testing/netemul/runner/model/environment.cc b/src/connectivity/network/testing/netemul/runner/model/environment.cc
index a9b9752..ec9b1ab 100644
--- a/src/connectivity/network/testing/netemul/runner/model/environment.cc
+++ b/src/connectivity/network/testing/netemul/runner/model/environment.cc
@@ -165,5 +165,14 @@
   return logger_options_;
 }
 
+void Environment::DisableLogging(bool recursive) {
+  logger_options_.set_enabled(false);
+  if (recursive) {
+    for (auto& child : children_) {
+      child.DisableLogging(recursive);
+    }
+  }
+}
+
 }  // namespace config
 }  // namespace netemul
diff --git a/src/connectivity/network/testing/netemul/runner/model/environment.h b/src/connectivity/network/testing/netemul/runner/model/environment.h
index 24f54e6..5fafc8a 100644
--- a/src/connectivity/network/testing/netemul/runner/model/environment.h
+++ b/src/connectivity/network/testing/netemul/runner/model/environment.h
@@ -20,6 +20,8 @@
   Environment() = default;
   Environment(Environment&& other) = default;
 
+  void DisableLogging(bool recursive);
+
   bool ParseFromJSON(const rapidjson::Value& value, json::JSONParser* parser);
 
   const std::string& name() const;
diff --git a/src/connectivity/network/testing/netemul/runner/model/logger_options.cc b/src/connectivity/network/testing/netemul/runner/model/logger_options.cc
index f7424aa..32757d0 100644
--- a/src/connectivity/network/testing/netemul/runner/model/logger_options.cc
+++ b/src/connectivity/network/testing/netemul/runner/model/logger_options.cc
@@ -72,6 +72,8 @@
   filters_.SetDefaults();
 }
 
+void LoggerOptions::set_enabled(bool enabled) { enabled_ = enabled; }
+
 bool LoggerOptions::enabled() const { return enabled_; }
 
 bool LoggerOptions::klogs_enabled() const { return klogs_enabled_; }
diff --git a/src/connectivity/network/testing/netemul/runner/model/logger_options.h b/src/connectivity/network/testing/netemul/runner/model/logger_options.h
index faf69bb..0e8869b 100644
--- a/src/connectivity/network/testing/netemul/runner/model/logger_options.h
+++ b/src/connectivity/network/testing/netemul/runner/model/logger_options.h
@@ -21,6 +21,7 @@
   bool ParseFromJSON(const rapidjson::Value& value, json::JSONParser* parser);
   void SetDefaults();
 
+  void set_enabled(bool enabled);
   bool enabled() const;
   bool klogs_enabled() const;
   const LoggerFilterOptions& filters() const;
diff --git a/src/connectivity/network/testing/netemul/runner/sandbox_unittest.cc b/src/connectivity/network/testing/netemul/runner/sandbox_unittest.cc
index 0418b81b..9716271 100644
--- a/src/connectivity/network/testing/netemul/runner/sandbox_unittest.cc
+++ b/src/connectivity/network/testing/netemul/runner/sandbox_unittest.cc
@@ -81,6 +81,8 @@
 
   void SetCmx(const std::string& cmx) {
     ASSERT_TRUE(sandbox_args_.ParseFromString(cmx));
+    // disable all syslog logging for unit tests.
+    sandbox_args_.config.environment().DisableLogging(true);
   }
 
   void EnableEventCollection() { collect_events_ = true; }