Fix Drupal 11.3 deprecation notices while preserving Drupal 10.3+ support

Problem/Motivation

Quick Tabs supports Drupal 10.3+ and Drupal 11:

The focused test suite passes, but Drupal 11.3 reports deprecation notices that should be fixed while preserving Drupal 10.3 compatibility.

The relevant deprecations are:

1. Functional test classes must specify the #[RunTestsInSeparateProcesses] attribute.
   Not doing so is deprecated in Drupal 11.3 and will throw an exception in Drupal 12.
2. Providing template_preprocess_quicktabs_view_quicktabs() directly is deprecated in Drupal 11.3 and removed in Drupal 12.
   Initial preprocess should be used instead.

Steps to reproduce

Run the focused tests on Drupal 11.3:

ddev exec vendor/bin/phpunit -c web/core/phpunit.xml.dist tests/src/Kernel/QuickTabsBlockCacheTest.php tests/src/Functional/QuickTabsAdminTest.php

The tests pass, but Drupal 11.3 reports deprecation notices for:

• Drupal\Tests\quicktabs\Functional\QuickTabsAdminTest
• template_preprocess_quicktabs_view_quicktabs()

Proposed resolution

Add #[RunTestsInSeparateProcesses] to QuickTabsAdminTest.php.

Add src/Hook/QuicktabsThemeHooks.php with preprocessQuicktabsViewQuicktabs() so Drupal 11.3 Views theme registration can use initial preprocess.

Keep template_preprocess_quicktabs_view_quicktabs() in quicktabs.module as a Drupal 10.3 compatibility delegate.

This keeps the existing Quick Tabs Views style template behavior while using the newer Drupal 11.3-compatible preprocess path where available.

Remaining tasks

• Review the Drupal 10.3 compatibility delegate.
• Confirm the Drupal 11.3 deprecation notices are resolved.
• Run coding standards and focused tests.

API changes

No API changes are expected.