@W-17964655: [Android] WSC discovery endpoint to postpone OAuth flow (#2736)

Author: JohnsonEricAtSalesforce

libs/SalesforceSDK/res/xml/servers.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <servers>
     <server name="Production" url="https://login.salesforce.com" />
-    <server name="Welcome" url="https://welcome.salesforce.com" />
+    <server name="Welcome" url="https://welcome.salesforce.com/discovery" />
     <server name="Sandbox" url="https://test.salesforce.com" />
 </servers>

libs/SalesforceSDK/src/com/salesforce/androidsdk/config/LoginServerManager.java

@@ -30,6 +30,7 @@
 import android.content.SharedPreferences;
 import android.content.SharedPreferences.Editor;
 import android.content.res.XmlResourceParser;
+import android.os.Looper;
 
 import androidx.annotation.NonNull;
 import androidx.lifecycle.MutableLiveData;
@@ -61,7 +62,7 @@ public class LoginServerManager {
 
 	// Default login servers.
 	public static final String PRODUCTION_LOGIN_URL = "https://login.salesforce.com";
-	public static final String WELCOME_LOGIN_URL = "https://welcome.salesforce.com";
+	public static final String WELCOME_LOGIN_URL = "https://welcome.salesforce.com/discovery";
 	public static final String SANDBOX_LOGIN_URL = "https://test.salesforce.com";
 
 	// Keys used in shared preferences.
@@ -167,7 +168,11 @@ public void setSelectedLoginServer(LoginServer server) {
 		edit.putString(SERVER_URL, server.url);
 		edit.putBoolean(IS_CUSTOM, server.isCustom);
 		edit.apply();
-		selectedServer.postValue(server);
+		if (Looper.myLooper() == Looper.getMainLooper()) {
+			selectedServer.setValue(server);
+		} else {
+			selectedServer.postValue(server);
+		}
 	}
 
 	/**