build: roll up to named .js files rather than 'index.js' (#19190)

PR Close #19190

packages/upgrade/static/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@angular/upgrade/static",
-  "typings": "./index.d.ts",
+  "typings": "./static.d.ts",
   "main": "../bundles/upgrade-static.umd.js",
-  "module": "../esm5/static/index.js",
-  "es2015": "../esm15/static/index.js"
+  "module": "../esm5/static.js",
+  "es2015": "../esm2015/static.js"
 }

packages/upgrade/static/rollup.config.js

@@ -14,7 +14,7 @@ const globals = {
 };
 
 export default {
-  entry: '../../../dist/packages-dist/upgrade/esm5/static/index.js',
+  entry: '../../../dist/packages-dist/upgrade/esm5/static.js',
   dest: '../../../dist/packages-dist/upgrade/bundles/upgrade-static.umd.js',
   format: 'umd',
   exports: 'named',

packages/upgrade/static/tsconfig-build.json

@@ -19,7 +19,7 @@
   ],
 
   "angularCompilerOptions": {
-    "flatModuleOutFile": "index.js",
+    "flatModuleOutFile": "static.js",
     "flatModuleId": "@angular/upgrade/static"
   }
 }