tests: Pin anvil to version 1.2.3

It seems that anvil 1.2.3 is the last version to produce deterministic
block hashes reliably. The 'grafted' test really needs deterministic block
hashes as they influence the PoI which this test checks.

If [this foundry bug](foundry-rs/foundry#9570)
gets fixed, we should try again with latest stable foundry.

Author: lutter

tests/docker-compose.yml

@@ -20,7 +20,7 @@ services:
       POSTGRES_DB: graph-node
       POSTGRES_INITDB_ARGS: "-E UTF8 --locale=C"
   anvil:
-    image: ghcr.io/foundry-rs/foundry:stable
+    image: ghcr.io/foundry-rs/foundry:v1.2.1
     ports:
       - '3021:8545'
     command: "'anvil --host 0.0.0.0 --gas-limit 100000000000 --base-fee 1 --block-time 2 --timestamp 1743944919 --mnemonic \"test test test test test test test test test test test junk\"'"