refactor(compiler): track the closing source-span of TagPlaceholders (#38645)

The `TagPlaceholder` can contain children, in which case there are two source
spans of interest: the opening tag and the closing tag. This commit now allows
the closing tag source-span to be tracked, so that it can be used later in
source-mapping.

PR Close #38645

packages/compiler/test/i18n/serializers/i18n_ast_spec.ts

@@ -41,7 +41,7 @@ import {_extractMessages} from '../i18n_parser_spec';
               new i18n.IcuPlaceholder(null!, '', null!),
             ],
             null!);
-        const tag = new i18n.TagPlaceholder('', {}, '', '', [container], false, null!);
+        const tag = new i18n.TagPlaceholder('', {}, '', '', [container], false, null!, null);
         const icu = new i18n.Icu('', '', {tag}, null!);
 
         icu.visit(visitor);