[13.x] Add multi-queue support to queue:clear command

[miladshakerdn]

Description

This PR adds support for comma-separated queue names to the queue:clear Artisan command, making it consistent with other queue commands such as queue:work and queue:listen.

Currently, queue:clear only accepts a single queue name via --queue. With this change, developers can clear multiple queues in a single execution:

php artisan queue:clear redis --queue=high,low,emails

Changes

• Updated Illuminate\Queue\Console\ClearCommand to parse, trim, filter empty values, and deduplicate comma-separated queue names using the Collection pipeline.
• Maintained output formatting consistency using standard Laravel Stringable helpers.
• Created unit test suite in tests/Queue/QueueClearCommandTest.php covering:
• Default single queue execution.
• Multiple comma-separated queues.
• Whitespace trimming (--queue="high, low").
• Empty value filtering (--queue="high,,low").
• Queue deduplication (--queue="high,low,high").

Backward Compatibility

Fully backward-compatible. Passing a single queue name behaves exactly as before.