fix(@angular-devkit/build-angular): normalize exclude path

[akhilbiju]

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?

The issue arises from passing exclude paths directly to the glob method, which can confuse users when they provide relative project roots or backslashes. This problem doesn't occur with include paths because those are automatically normalized.

Issue Number: #26239

What is the new behavior?

The exclude paths are now normalized for common user errors, such as the use of backslashes or relative project roots. This also unifies, to a certain extent, how include and exclude paths are transformed internally by the builder.

The remaining normalization steps for include are already informed to the developer, so now all the normalization for include & exclude are either unified or documented.

Does this PR introduce a breaking change?

• Yes
• No

Other information

[akhilbiju]

Update:

1. Fixed lint errors
2. Refactored code
3. Squashed all the commits into one

[akhilbiju]

Update:

1. Added tests
2. Fixed format issues
3. Rebased the branch

@alan-agius4 -> Please, review.

[alan-agius4]

LGTM, thanks for your contribution

[akhilbiju]

@alan-agius4 -> I hope we are good to merge this?

[alan-agius4]

@akhilbiju, yes, CI is green.

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}