refactor(ivy): avoid type coercion in `saveNameToExportMap` function (#34335)

TypeScript 3.7 flags `if` conditions that implicitly coerce a function/method definition. While checking for the `template` presence on a def (actually checking whether we work with Component) in `saveNameToExportMap`, the `if` condition had implicit type coercion. This commit updates the condition to use the `isComponentDef` function (that checks `def.template` against `null` internally) to avoid compilation errors with TypeScript 3.7.

PR Close #34335

packages/core/src/render3/instructions/shared.ts

@@ -1304,7 +1304,7 @@ function saveNameToExportMap(
         exportsMap[def.exportAs[i]] = index;
       }
     }
-    if ((def as ComponentDef<any>).template) exportsMap[''] = index;
+    if (isComponentDef(def)) exportsMap[''] = index;
   }
 }