geonetwork.wro4j error _custom_style when having a sub-portal

Having an additional sub-portal creates this wro4j error that keeps reoccuring
```
2024-07-29T11:15:01,133 ERROR [geonetwork.wro4j] - Error occurred during a wro4j request handling
ro.isdc.wro.WroRuntimeException: No such group available in the model: metawal-hvd-portal_custom_style
at ro.isdc.wro.model.group.processor.GroupsProcessor.process(GroupsProcessor.java:74) ~[wro4j-core-1.10.1.jar:1.10.1]
at ro.isdc.wro.cache.support.DefaultSynchronizedCacheStrategyDecorator.loadValue(DefaultSynchronizedCacheStrategyDecorator.java:101) ~[wro4j-core-1.10.1.jar:1.10.1]
at ro.isdc.wro.cache.support.DefaultSynchronizedCacheStrategyDecorator.loadValue(DefaultSynchronizedCacheStrategyDecorator.java:35) ~[wro4j-core-1.10.1.jar:1.10.1]
at ro.isdc.wro.cache.support.AbstractSynchronizedCacheStrategyDecorator.get(AbstractSynchronizedCacheStrategyDecorator.java:55) ~[wro4j-core-1.10.1.jar:1.10.1]
at ro.isdc.wro.manager.ResourceBundleProcessor.serveProcessedBundle(ResourceBundleProcessor.java:64) ~[wro4j-core-1.10.1.jar:1.10.1]
at ro.isdc.wro.manager.WroManager.process(WroManager.java:159) ~[wro4j-core-1.10.1.jar:1.10.1]
at ro.isdc.wro.http.WroFilter.processRequest(WroFilter.java:344) ~[wro4j-core-1.10.1.jar:1.10.1]
at ro.isdc.wro.http.WroFilter.doFilter(WroFilter.java:299) ~[wro4j-core-1.10.1.jar:1.10.1]
at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1626) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.fao.geonet.web.XFrameOptionsFilter.doFilter(XFrameOptionsFilter.java:110) ~[gn-core-4.4.6-SNAPSHOT.jar:?]
at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1626) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:176) ~[urlrewritefilter-4.0.3.jar:4.0.3]
at org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:145) ~[urlrewritefilter-4.0.3.jar:4.0.3]
at org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:92) ~[urlrewritefilter-4.0.3.jar:4.0.3]
at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:394) ~[urlrewritefilter-4.0.3.jar:4.0.3]
at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1626) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.fao.geonet.web.CORSResponseFilter.doFilter(CORSResponseFilter.java:133) ~[gn-core-4.4.6-SNAPSHOT.jar:?]
at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1626) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.fao.geonet.web.GeoNetworkPortalFilter.doFilter(GeoNetworkPortalFilter.java:103) ~[gn-core-4.4.6-SNAPSHOT.jar:?]
at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1626) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:218) ~[spring-security-web-5.8.11.jar:5.8.11]
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:190) ~[spring-security-web-5.8.11.jar:5.8.11]
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:354) ~[spring-web-5.3.33.jar:5.3.33]
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:267) ~[spring-web-5.3.33.jar:5.3.33]
at jeeves.config.springutil.JeevesDelegatingFilterProxy.doFilter(JeevesDelegatingFilterProxy.java:74) ~[gn-core-4.4.6-SNAPSHOT.jar:?]
at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1626) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.33.jar:5.3.33]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.33.jar:5.3.33]
at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:201) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1626) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:552) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:600) ~[jetty-security-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:235) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1624) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1440) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:505) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1594) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1355) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:191) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:146) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.Server.handle(Server.java:516) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:487) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:732) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:479) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:277) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311) ~[jetty-io-9.4.18.v20190429.jar:9.4.18.v20190429]
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:105) ~[jetty-io-9.4.18.v20190429.jar:9.4.18.v20190429]
at org.eclipse.jetty.io.ChannelEndPoint$1.run(ChannelEndPoint.java:104) ~[jetty-io-9.4.18.v20190429.jar:9.4.18.v20190429]
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:338) ~[jetty-util-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:315) ~[jetty-util-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:173) ~[jetty-util-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:131) ~[jetty-util-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:409) ~[jetty-util-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:883) ~[jetty-util-9.4.54.v20240208.jar:9.4.54.v20240208]
at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:1034) ~[jetty-util-9.4.54.v20240208.jar:9.4.54.v20240208]
at java.lang.Thread.run(Thread.java:829) ~[?:?]
```
Generates this log in developer tools window as well:
`GET /static/metawal-hvd-portal_custom_style.css?v=0b89294accf7c842a085cfd429c36c733fff70b0& net::ERR_ABORTED 404 (Not Found)`

Start with the wro4j stack trace, especially GroupsProcessor.process, and the failing request for /static/metawal-hvd-portal_custom_style.css. Reproduce the error with an additional sub-portal and trace how the custom-style group is assembled; done means the request no longer returns a 404 or logs the missing-group error.

Written by the indexing model from the issue text.