fix: name generated engine classes from schema titles

Upstream 58eb348 added a `flags` property to the evaluation context.
jsonschema2pojo names classes from the property name, so it collided with
the evaluation result's `flags`: one became Flags__1 and Engine.java no
longer compiled. CI had failed on every branch since 2026-08-31.

Name classes from the schema title instead. Every object in the upstream
schemas has a unique title matching its current generated name, so the
generated set is unchanged apart from the new FlagResults (titled so by
upstream Flagsmith/flagsmith#8581). The schema refs keep tracking main.

Author: Zaimwa9

pom.xml

@@ -227,6 +227,7 @@
           <targetPackage>com.flagsmith.flagengine</targetPackage>
           <outputDirectory>${project.build.directory}/generated-sources/jsonschema2pojo</outputDirectory>
           <generateBuilders>true</generateBuilders>
+          <useTitleAsClassname>true</useTitleAsClassname>
           <includeConstructors>true</includeConstructors>
           <includeCopyConstructor>true</includeCopyConstructor>
         </configuration>