Update CelBindingsExtensions class visibility to public

PiperOrigin-RevId: 835147547

Author: Stephen Roberts

extensions/src/main/java/dev/cel/extensions/CelBindingsExtensions.java

@@ -31,7 +31,8 @@
 
 /** Internal implementation of the CEL local binding extensions. */
 @Immutable
-final class CelBindingsExtensions implements CelCompilerLibrary, CelExtensionLibrary.FeatureSet {
+public final class CelBindingsExtensions
+    implements CelCompilerLibrary, CelExtensionLibrary.FeatureSet {
   private static final String CEL_NAMESPACE = "cel";
   private static final String UNUSED_ITER_VAR = "#unused";