feat : E2E test for Create backfill with all reprocess behaviour

[iharsh02]

E2E test for Create backfill with all reprocess behaviour

• Navigate to Backfills tab - Verify the backfills tab exists and is accessible
• Create backfill with "reprocess none" (Missing Runs) behavior - Default behavior
• Create backfill with "reprocess failed" (Missing and Errored Runs) behavior
• Create backfill with "reprocess completed" (All Runs) behavior
• Verify backfill appears in list after creation
• Verify validation errors for invalid date range - Start date after end date

Closes : #59593
Related: #59028

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[vatsrahul1001]

@iharsh02 Can you look at failing test?

[vatsrahul1001]

@iharsh02 I see for failures for firefox.

Also for webkit there were reruns due to a default timeout of 30000ms and in later run it passed.

Can we increase timeout for this element ?

[vatsrahul1001]

@iharsh02 can you resolve conflicts and address review comments?

[iharsh02]

@iharsh02 can you resolve conflicts and address review comments?

Will work on this today

[vatsrahul1001]

@iharsh02 Instead of a separate test.describe("Backfill creation"), let's consolidate:

1. Add creation of "Missing Runs" and "Missing and Errored Runs" to the existing beforeAll in "Backfills List Display"
2. Add a test to verify all three reprocess behaviors exist in the table
3. Keep only the date validation test as a separate small describe block

This avoids duplicate test setup and makes the test structure cleaner.

[iharsh02]

@vatsrahul1001 Looks like indexing of the table column is not working and its flaky too , I was indexing the table data to identify the row and using the createFormDate and createToDate , can you guide me how we can proceed further