Car: remove usage of WifiConfig helper methods

These methods can be replaced with methods on
IpConfiguration itself. There is no need to expose
these as a @SystemApi, and they are being removed.

Bug: 146046526
Test: compiles
Change-Id: Ica0cba567865fae86a60ced696069d5d2ad4b98a
diff --git a/tests/CarDeveloperOptions/src/com/android/car/developeroptions/wifi/WifiConfigController.java b/tests/CarDeveloperOptions/src/com/android/car/developeroptions/wifi/WifiConfigController.java
index 61abd4c..4d88bdc 100644
--- a/tests/CarDeveloperOptions/src/com/android/car/developeroptions/wifi/WifiConfigController.java
+++ b/tests/CarDeveloperOptions/src/com/android/car/developeroptions/wifi/WifiConfigController.java
@@ -287,11 +287,12 @@
                                 config.macRandomizationSetting);
                 mPrivacySettingsSpinner.setSelection(prefMacValue);
 
-                if (config.getIpAssignment() == IpAssignment.STATIC) {
+                if (config.getIpConfiguration().getIpAssignment() == IpAssignment.STATIC) {
                     mIpSettingsSpinner.setSelection(STATIC_IP);
                     showAdvancedFields = true;
                     // Display IP address.
-                    StaticIpConfiguration staticConfig = config.getStaticIpConfiguration();
+                    StaticIpConfiguration staticConfig = config.getIpConfiguration()
+                            .getStaticIpConfiguration();
                     if (staticConfig != null && staticConfig.ipAddress != null) {
                         addRow(group, R.string.wifi_ip_address,
                                 staticConfig.ipAddress.getAddress().getHostAddress());
@@ -305,10 +306,11 @@
                     showAdvancedFields = true;
                 }
 
-                if (config.getProxySettings() == ProxySettings.STATIC) {
+                ProxySettings proxySettings = config.getIpConfiguration().getProxySettings();
+                if (proxySettings == ProxySettings.STATIC) {
                     mProxySettingsSpinner.setSelection(PROXY_STATIC);
                     showAdvancedFields = true;
-                } else if (config.getProxySettings() == ProxySettings.PAC) {
+                } else if (proxySettings == ProxySettings.PAC) {
                     mProxySettingsSpinner.setSelection(PROXY_PAC);
                     showAdvancedFields = true;
                 } else {
@@ -1230,7 +1232,8 @@
                 mDns2View.addTextChangedListener(this);
             }
             if (config != null) {
-                StaticIpConfiguration staticConfig = config.getStaticIpConfiguration();
+                StaticIpConfiguration staticConfig = config.getIpConfiguration()
+                        .getStaticIpConfiguration();
                 if (staticConfig != null) {
                     if (staticConfig.ipAddress != null) {
                         mIpAddressView.setText(