Sync create indexes for ci_sources_pipelines pipeline_id conversion

What does this MR do and why?

Sync create indexes for ci_sources_pipelines pipeline_id conversion

This is the second step to synchronously create indexes for ci_sources_pipelines

See https://docs.gitlab.com/ee/development/database/adding_database_indexes.html#add-a-migration-to-create-the-index-synchronously

See the following output from postgres.ai that async index is completed on prod:

Table "public.ci_sources_pipelines"
                Column                |  Type   | Collation | Nullable |                     Default                      | Storage | Compression | Stats target | Description 
--------------------------------------+---------+-----------+----------+--------------------------------------------------+---------+-------------+--------------+-------------
 id                                   | integer |           | not null | nextval('ci_sources_pipelines_id_seq'::regclass) | plain   |             |              | 
 project_id                           | integer |           |          |                                                  | plain   |             |              | 
 pipeline_id                          | integer |           |          |                                                  | plain   |             |              | 
 source_project_id                    | integer |           |          |                                                  | plain   |             |              | 
 source_pipeline_id                   | integer |           |          |                                                  | plain   |             |              | 
 source_job_id                        | bigint  |           |          |                                                  | plain   |             |              | 
 partition_id                         | bigint  |           | not null |                                                  | plain   |             |              | 
 source_partition_id                  | bigint  |           | not null |                                                  | plain   |             |              | 
 pipeline_id_convert_to_bigint        | bigint  |           |          |                                                  | plain   |             |              | 
 source_pipeline_id_convert_to_bigint | bigint  |           |          |                                                  | plain   |             |              | 
Indexes:
    "ci_sources_pipelines_pkey" PRIMARY KEY, btree (id)
    "index_ci_sources_pipelines_on_pipeline_id" btree (pipeline_id)
    "index_ci_sources_pipelines_on_pipeline_id_bigint" btree (pipeline_id_convert_to_bigint)
    "index_ci_sources_pipelines_on_project_id" btree (project_id)
    "index_ci_sources_pipelines_on_source_job_id" btree (source_job_id)
    "index_ci_sources_pipelines_on_source_partition_id_source_job_id" btree (source_partition_id, source_job_id)
    "index_ci_sources_pipelines_on_source_pipeline_id" btree (source_pipeline_id)
    "index_ci_sources_pipelines_on_source_pipeline_id_bigint" btree (source_pipeline_id_convert_to_bigint)
    "index_ci_sources_pipelines_on_source_project_id" btree (source_project_id)
Foreign-key constraints:
    "fk_be5624bf37_p" FOREIGN KEY (source_partition_id, source_job_id) REFERENCES p_ci_builds(partition_id, id) ON UPDATE CASCADE ON DELETE CASCADE
    "fk_d4e29af7d7" FOREIGN KEY (source_pipeline_id) REFERENCES ci_pipelines(id) ON DELETE CASCADE
    "fk_e1bad85861" FOREIGN KEY (pipeline_id) REFERENCES ci_pipelines(id) ON DELETE CASCADE
Triggers:
    trigger_68d7b6653c7d BEFORE INSERT OR UPDATE ON ci_sources_pipelines FOR EACH ROW EXECUTE FUNCTION trigger_68d7b6653c7d()
Access method: heap

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Related to #422826 (closed)