[v5] Update Angular and Node version support

[tnorling]

Update version support matrix for Node and Angular in v5

• Drops support for Angular 15,16, and 17 (Consistent with Angular's own support stance)
• Updates Angular samples to Angular 20 + updates docs indicating support for Angular 20
• Drops support for Node 16 and 18 (Consistent with Node's own support stance)
• Adds Node 24 to test matrix

[Copilot]

Pull Request Overview

This PR updates the version support matrix for both Angular and Node in v5, aligning with their respective LTS and deprecation schedules. It bumps sample apps to Angular 20 (and adjusts builders and TS settings), drops older Node versions in CI while adding Node 24, and updates documentation and pipelines accordingly.

• Updated sample configurations (tsconfig.json, package.json, angular.json) to use Angular 20, switch to new builders, and use moduleResolution: "bundler".
• Updated support tables in documentation to reflect Angular 20 and Node 24 support.
• Adjusted CI pipeline to test against Node 20, 22, 24 instead of Node 16, 18.

Reviewed Changes

Copilot reviewed 17 out of 18 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
samples/*/tsconfig.json	Switched moduleResolution to "bundler"
samples/*/package.json	Bumped Angular dependencies to ^20.x.x, TS to 5.8
samples/*/angular.json	Switched builders to @angular/build, added schematics
samples/msal-angular-samples/angular-b2c-sample/karma.conf.js	Removed Angular DevKit Karma plugin incorrectly
samples/msal-angular-samples/README.md	Updated description to Angular 20
lib/msal-node/README.md	Updated Node support table for v4, v3, v2
lib/msal-angular/README.md	Updated Angular support table for v5 and v4
.pipelines/3p-e2e.yml	Updated CI Node versions to [20, 22, 24]

Comments suppressed due to low confidence (3)

lib/msal-angular/README.md:50

• [nitpick] Having two consecutive versions marked as "Active development" (v5 and v4) may confuse readers. If v4 is no longer receiving new features, consider changing its status to "In maintenance" to improve clarity.

| MSAL Angular v4      | Active development  | 15, 16, 17, 18, 19, 20     |

samples/msal-angular-samples/angular-standalone-sample/angular.json:133

• [nitpick] The schematics block is duplicated across multiple sample angular.json files. Consider extracting these common settings into a shared base or central config to reduce duplication.

  "schematics": {