[12.x] Add test coverage for filtering failed jobs by connection and queue

[roshandelpoor]

This PR adds a new test case to enhance the test coverage of the DatabaseFailedJobProvider class. The new test specifically verifies the ability to filter and retrieve failed jobs by both connection and queue simultaneously.

Added Test Case

• Added testCanRetrieveFailedJobsByConnectionAndQueue() which verifies:
  • Multiple failed jobs can be stored with different connections and queues
  • Jobs can be accurately filtered by both connection and queue parameters
  • Exception messages are properly stored and retrieved
  • Filtering correctly excludes jobs from other connections and queues