Address the Primary Key Overflow risk for the ci_sources_pipelines table - Step 3: Drop temporary columns and triggers

Instead of creating issues for each step, the work for the steps is outlined below. An MR will be created for each of the steps.

• Step 1:
  • Ignore column source_job_id_convert_to_bigint
  • Drop trigger to keep columns in sync
• Step 2: Dropping the column (release m+1)
• Step 3: Removing the ignore rule (release m+2)