chore: remove usused pg_notify code #6673

Job	Run time
Lint	1m 47s
SQL	1m 5s
Test Go	2m 44s
Test README	1m 28s
Test Scripts	9s
Lint Architecture	11s
Console	1m 8s
Build Docs	10s
Ensure Frozen Migrations	7s
Proto Breaking Change Check	6s
VSCode Extension	39s
Rebuild All	0s
Build Controller Docker Image	0s
Build Box Docker Image	0s
Build Runner Docker Image	0s
Console e2e	0s
Shard Integration Tests	0s
Integration Test	0s
Integration Success	3s
	9m 37s

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