fix: work around cjs interop quirks of api-kit

src/execute/execute.ts

@@ -1,6 +1,7 @@
 import assert from 'assert'
 import {
   Address,
+  Chain,
   createWalletClient,
   custom,
   defineChain,
@@ -121,7 +122,7 @@ export const execute = async (
           })
         )
 
-        const apiKit = new SafeApiKit({ chainId: BigInt(chain) })
+        const apiKit = initApiKit(chain)
         await apiKit.proposeTransaction({
           safeAddress: safe,
           safeTransactionData: {
@@ -150,6 +151,17 @@ export const execute = async (
   }
 }
 
+// TODO: remove this once https://github.com/safe-global/safe-core-sdk/issues/514 is closed
+const initApiKit = (chainId: ChainId) => {
+  // @ts-expect-error SafeApiKit is only available as a CJS module. That doesn't play super nice with us being ESM.
+  if (SafeApiKit.default) {
+    // @ts-expect-error See above
+    return new SafeApiKit.default({ chainId: BigInt(chainId) })
+  }
+
+  return new SafeApiKit({ chainId: BigInt(chainId) })
+}
+
 const _getWalletClient = ({
   chain,
   account,