SLING-9159 - Switch to the LazyBindings implementation from org.apache.sling.api

* the suppliers map should be modifiable
diff --git a/main/java/org/apache/sling/scripting/bundle/tracker/internal/ScriptContextProvider.java b/main/java/org/apache/sling/scripting/bundle/tracker/internal/ScriptContextProvider.java
index 85b0f98..3ab0ffd 100644
--- a/main/java/org/apache/sling/scripting/bundle/tracker/internal/ScriptContextProvider.java
+++ b/main/java/org/apache/sling/scripting/bundle/tracker/internal/ScriptContextProvider.java
@@ -97,7 +97,7 @@
         Map<String, LazyBindings.Supplier> slingBindingsSuppliers = new HashMap<>();
         slingBindingsSuppliers.put(SlingScriptConstants.ATTR_SCRIPT_RESOURCE_RESOLVER,
                 () -> scriptingResourceResolverProvider.getRequestScopedResourceResolver());
-        LazyBindings slingScopeBindings = new LazyBindings(Collections.unmodifiableMap(slingBindingsSuppliers));
+        LazyBindings slingScopeBindings = new LazyBindings(slingBindingsSuppliers);
         scriptContext.setBindings(slingScopeBindings, SlingScriptConstants.SLING_SCOPE);
         scriptContext.setBindings(bindings, ScriptContext.ENGINE_SCOPE);
         scriptContext.setWriter(response.getWriter());