chore: speed up ng generate component schematic

[sebawita]

Replace the use of filter() with tree.delete()

This significantly improves the performance of generating components, as filter() is a very slow function, which goes through every single file (including all files in node_modules) to check for the filtering condition.

PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
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• All existing tests are passing: https://github.com/NativeScript/nativescript-schematics/blob/master/CONTRIBUTING.md#running-tests.
• Tests for the changes are included.

What is the current behavior?

What is the new behavior?

Fixes/Implements/Closes #[Issue Number].