fix: improve perf of GetValidatorDepositsAndIncomingConsolidations, add idx_blocks_deposit_requests_v2_pubkey

Author: guybrush

backend/pkg/commons/db/migrations/postgres/20250826095322_add_idx_blocks_deposit_requests_v2_pubkey.sql

@@ -0,0 +1,13 @@
+-- +goose NO TRANSACTION
+
+-- +goose Up
+SELECT 'create idx_blocks_deposit_requests_v2_pubkey';
+-- +goose StatementBegin
+CREATE INDEX CONCURRENTLY IF NOT EXISTS idx_blocks_deposit_requests_v2_pubkey ON blocks_deposit_requests_v2 (pubkey);
+-- +goose StatementEnd
+
+-- +goose Down
+SELECT 'drop idx_blocks_deposit_requests_v2_pubkey';
+-- +goose StatementBegin
+DROP INDEX CONCURRENTLY IF EXISTS idx_blocks_deposit_requests_v2_pubkey;
+-- +goose StatementEnd