Remove single column FKs `ci_builds`

Problem

We are currently redefining all FKs referencing ci_builds to make sure it includes partition_id as this is mandatory in order to successfully partition this table.

Once all FKS will be created, we can get rid of FK not including partition_id.

Solution

• Remove single column FKs ci_builds

Table name	FK name	Removable?	Removed
ci_unit_test_failures	fk_0f09856e1f	✅	✅
ci_sources_pipelines	fk_be5624bf37	✅	✅
ci_resources	fk_e169a8e3d5	✅	✅
ci_build_pending_states	fk_rails_0bbbfeaf9d	✅	✅
ci_build_trace_chunks	fk_rails_1013b761f2	✅	✅
ci_build_report_results	fk_rails_16cb1ff064	✅	✅
ci_build_needs	fk_rails_3cf221d4ed	✅	✅
ci_builds_runner_session	fk_rails_70707857d3	✅	✅
ci_pending_builds	fk_rails_725a2644a3	✅	✅
ci_build_trace_metadata	fk_rails_aebc78111f	✅	✅
ci_job_artifacts	fk_rails_c5137cb2c1	✅	✅
ci_running_builds	fk_rails_da45cfa165	✅	✅
ci_job_variables	fk_rails_fbf3b34792	✅	✅

❌ in the Removable? column means that the composite FK was not created & validated yet.