fix(@angular/build): add browser condition to resolver for vitest

[jeripeierSBB]

PR Checklist

Please check to confirm your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/angular/angular-cli/blob/main/CONTRIBUTING.md#-commit-message-guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation content changes
• Other... Please describe:

What is the current behavior?

Given a package.json like following:

{
  "name": "browser-condition",
  "type": "module",
  "exports": {
    ".": {
      "browser": {
        "default": "./browser.js"
      },
      "node": {
        "default": "./node.js"
      },
      "default": "./browser.js"
    }
  }
}

Currently, when using vitest, even when testing in real browser, it takes the "node.js" module.
This, for example, happens when using lit components, which are depending on isServer const in tests as they load different modules depending on the environment.

Issue Number: N/A

What is the new behavior?

Respects the "browser" condition when testing in a real browser and chooses "browser.js" in the above example.

Does this PR introduce a breaking change?

• Yes
• No

Other information

We face difficulties, trying to create a test case.
We tried to add a test like following, but the problem is that the dependency @vitest/browser-playwright is missing in unit tests. Should it be installed? Or more general, what would be the best way to create a test case?.

    it('should resolve browser condition', async () => {
      await harness.modifyFile('tsconfig.json', (content) => {
        const tsConfig = JSON.parse(content);
        tsConfig.compilerOptions.paths = {
          'browser-condition': ['browser-condition'],
        };

        return JSON.stringify(tsConfig);
      });

      await harness.writeFile('browser-condition/browser.js', "export const value = 'browser';");
      await harness.writeFile('browser-condition/node.js', "export const value = 'node';");

      const packageJson = {
        name: 'browser-condition',
        type: 'module',
        exports: {
          '.': {
            browser: {
              default: './browser.js',
            },
            node: {
              default: './node.js',
            },
            default: './browser.js',
          },
        },
      };

      await harness.writeFile(
        'browser-condition/package.json',
        JSON.stringify(packageJson, null, 2),
      );

      await harness.modifyFile('src/app/app.component.ts', (content) => {
        return (
          `import { value } from 'browser-condition';\n` +
          content.replace(`title = 'app';`, 'title = value;')
        );
      });

      await harness.modifyFile('src/app/app.component.spec.ts', (content) => {
        return content.replace(
          `expect(app.title).toEqual('app');`,
          `expect(app.title).toEqual('browser');`,
        );
      });

      harness.useTarget('test', {
        ...BASE_OPTIONS,
        browsers: ['chrome'],
      });

      const { result } = await harness.executeOnce();
      expect(result?.success).toBeTrue();
    })

[hybrist]

Sorry for missing this one in today's release a few hours ago!

[hybrist]

This PR was merged into the repository. The changes were merged into the following branches:

• main: 98c207b
• 21.0.x: deb4fff