Test(UI): Add E2E test for verify task logs display

[vighneshtule]

This PR adds an E2E test to verify that the Task Logs view is functioning correctly.

Changes:

• TaskInstancePage.ts: Created a new Page Object to handle interactions with the Task Instance view, specifically the logs tab. Added locators for the log container, log entries, and the download button.
• task-logs.spec.ts: Added a new test specification that:
  • Triggers a DAG run (example_bash_operator).
  • Navigates to the logs view of a task instance.
  • Verifies the log container is visible and populated.
  • Verifies the "Download" button is present and enabled.

related: #59528

Was generative AI tooling used to co-author this PR?

• Yes