include plugin name in cache key. Fixes #10339

Author: graemerocher

grails-web-gsp/src/main/groovy/org/grails/web/gsp/GroovyPagesTemplateRenderer.java

@@ -134,7 +134,12 @@ private Template findAndCacheTemplate(Object controller, TemplateVariableBinding
         if (scriptSource == null) {
             cacheKey = contextPath + pluginName + uri;
         } else {
-            cacheKey = scriptSource.getURI();
+            if(pluginName != null) {
+                cacheKey = contextPath + pluginName + scriptSource.getURI();
+            }
+            else {
+                cacheKey = scriptSource.getURI();
+            }
         }
 
         return CacheEntry.getValue(templateCache, cacheKey, reloadEnabled ? GroovyPageMetaInfo.LASTMODIFIED_CHECK_INTERVAL : -1, null,