feat(kms-connector): retrieve s3 url in extra_data

coprocessor/fhevm-engine/db-migration/migrations/20250924120045_verify_proofs_coprocessor_context_id.sql

@@ -0,0 +1,8 @@
+-- Use a default context ID of 1 as this is the first one used by the GW contract.
+-- Note that if this migration is run after context ID has changed, the proof requests still pending would fail.
+-- Therefore, we assume that this migration runs when either:
+--  * the table is empty
+--  * context ID is currently 1
+ALTER TABLE verify_proofs
+ADD COLUMN IF NOT EXISTS coprocessor_context_id
+BYTEA NOT NULL DEFAULT decode('0100000000000000000000000000000000000000000000000000000000000000', 'hex');