perf(@angular/cli): avoid redundant package version resolution in ng add

The `ng add` command would previously resolve the package version from the
registry multiple times during execution. This change updates the package
identifier with the exact version from the manifest once it has
been fetched from the registry, preventing subsequent redundant lookups.
Additionally, the already-parsed package identifier is now passed directly
to the package manager's `getManifest` method.

Author: clydin

packages/angular/cli/src/commands/add/cli.ts

@@ -489,12 +489,9 @@ export default class AddCommandModule
 
     let manifest;
     try {
-      manifest = await this.context.packageManager.getManifest(
-        context.packageIdentifier.toString(),
-        {
-          registry,
-        },
-      );
+      manifest = await this.context.packageManager.getManifest(context.packageIdentifier, {
+        registry,
+      });
     } catch (e) {
       assertIsError(e);
       throw new CommandError(
@@ -508,6 +505,12 @@ export default class AddCommandModule
       );
     }
 
+    // Avoid resolving the package version from the registry again in later steps
+    if (context.packageIdentifier.registry) {
+      assert(context.packageIdentifier.name, 'Registry package identifier must have a name');
+      context.packageIdentifier = npa.resolve(context.packageIdentifier.name, manifest.version);
+    }
+
     context.hasSchematics = !!manifest.schematics;
     context.savePackage = manifest['ng-add']?.save;
     context.collectionName = manifest.name;