feat(compiler): support safe keyed read expressions (#41911)

Currently we support safe property (`a?.b`) and method (`a?.b()`) accesses, but we don't handle safe keyed reads (`a?.[0]`) which is inconsistent. These changes expand the compiler in order to support safe key read expressions as well.

PR Close #41911

packages/compiler/test/template_parser/util/expression.ts

@@ -114,6 +114,10 @@ class ExpressionSourceHumanizer extends e.RecursiveAstVisitor implements t.Templ
     this.recordAst(ast);
     super.visitQuote(ast, null);
   }
+  visitSafeKeyedRead(ast: e.SafeKeyedRead) {
+    this.recordAst(ast);
+    super.visitSafeKeyedRead(ast, null);
+  }
 
   visitNgContent(ast: t.NgContentAst) {}
   visitEmbeddedTemplate(ast: t.EmbeddedTemplateAst) {