An attempt to fix flaky zksync test (#898)

- Upgraded several development dependencies related to Hardhat and
zkSync:
  - `@matterlabs/hardhat-zksync-deploy` from `^1.5.0` to `^1.6.0`
  - `@matterlabs/hardhat-zksync-node` from `^1.1.1` to `^1.2.1`
  - `@matterlabs/hardhat-zksync-verify` from `^1.6.0` to `^1.7.1`
  - `zksync-ethers` from `6.12.1` to `6.15.3`
- Refactored the test setup in `SafeToL2Setup.spec.ts` to retrieve the
deployed contract instance using `getContractAt` instead of deploying a
new instance, enhancing test reliability and efficiency.

hardhat.config.ts

@@ -89,8 +89,10 @@ const userConfig: HardhatUserConfig = {
         compilers: [{ version: primarySolidityVersion, settings: soliditySettings }, { version: defaultSolidityVersion }],
     },
     zksolc: {
-        version: "1.5.3",
-        settings: {},
+        version: "1.5.9",
+        settings: {
+            suppressedErrors: ["assemblycreate"],
+        },
     },
     networks: {
         hardhat: {