fix: set tagName on NgView for Angular 21 bootstrap compatibility

[Copilot]

This PR isolates commit 17173d2e3714d8bcb23d466557d34fd627f79a07 into a standalone change.
It addresses Angular 21 bootstrap behavior where locateHostElement reads rootElement.tagName.toLowerCase(), which can throw when NativeScript root elements lack a string tagName.

• Root-element compatibility guard

  • Updated selectRootElement in packages/angular/src/lib/nativescript-renderer.ts to normalize all return paths through a local ensureTagName(...) helper.
  • Ensures returned views expose a string tagName (derived from nodeName, selector fallback, or 'view').

• Behavioral scope

  • Applies to all existing selectRootElement branches:
    • direct View input
    • #id lookup path
    • string selector that creates/appends a view
    • default fallback to rootView
  • No unrelated files are modified.

const ensureTagName = (view: any, fallback: string) => {
  if (view && typeof view.tagName !== 'string') {
    try {
      view.tagName = view.nodeName || fallback || 'view';
    } catch {}
  }
  return view;
};

Original prompt

Create a pull request in NativeScript/angular that contains only commit 17173d2e3714d8bcb23d466557d34fd627f79a07 (fix: set tagName on NgView for Angular 21 bootstrap compatibility).

Requirements:

• The PR should cherry-pick or otherwise include exactly the changes from commit 17173d2e3714d8bcb23d466557d34fd627f79a07 and no unrelated changes.
• Use the commit message as the basis for the PR title: fix: set tagName on NgView for Angular 21 bootstrap compatibility.
• The PR should modify only packages/angular/src/lib/nativescript-renderer.ts with the changes from that commit.
• Base the PR against the repository's appropriate default/base branch unless repository context indicates otherwise.
• In the PR description, mention that this isolates commit 17173d2e3714d8bcb23d466557d34fd627f79a07 into a standalone PR.

Context from the commit:

• Parent commit: d9d49dcb532e88555293ee6a892112f7821c0b25
• File changed: packages/angular/src/lib/nativescript-renderer.ts
• Intent: ensure selectRootElement always returns a View with a string tagName so Angular 21 bootstrap compatibility checks do not throw when calling rootElement.tagName.toLowerCase().

The following is the prior conversation context from the user's chat exploration (may be truncated):

User: Could you post a pull request with just this commit?

Assistant: I’m waiting for your confirmation on the pull request action, and once you approve it I can continue.

This pull request was created from Copilot chat.

[NathanWalker]

This is missing files, closing in favor of: #168