feat: added manual .builder() method to UserContext to align to the documentation

Author: crossbone-magister

lib/src/main/java/growthbook/sdk/java/multiusermode/configurations/UserContext.java

@@ -1,8 +1,8 @@
 package growthbook.sdk.java.multiusermode.configurations;
 
 import com.google.gson.JsonObject;
-import growthbook.sdk.java.multiusermode.util.TransformationUtil;
 import growthbook.sdk.java.model.StickyAssignmentsDocument;
+import growthbook.sdk.java.multiusermode.util.TransformationUtil;
 import lombok.Setter;
 import lombok.extern.slf4j.Slf4j;
 
@@ -41,6 +41,10 @@ private UserContext(UserContextBuilder userContextBuilder) {
         attributesJson = userContextBuilder.attributesJson;
     }
 
+    public static UserContextBuilder builder() {
+        return new UserContextBuilder();
+    }
+
     public UserContext witAttributesJson(String attributesJson) {
         // Build a new context using only the provided attributesJson for attributes
         return new UserContextBuilder()