test: append-more-multisigmIsm-test (#4769)

### Description
Append more test for `multisigIsm.ts`
<!--
What's included in this PR?
-->

### Drive-by changes

<!--
Are there any minor or drive-by changes also included?
-->

### Related issues

<!--
- Fixes #[issue number here]
-->

### Backward compatibility

<!--
Are these changes backward compatible? Are there any infrastructure
implications, e.g. changes that would prohibit deploying older commits
using this infra tooling?

Yes/No
-->

### Testing
Add 2 test cases:
- has a valid number of validators for each threshold
- has valid EVM addresses for each validator
<!--
What kind of testing have these changes undergone?

None/Manual/Unit Tests
-->

typescript/sdk/src/consts/multisigIsm.test.ts

@@ -1,5 +1,7 @@
 import { expect } from 'chai';
 
+import { isAddress } from '@hyperlane-xyz/utils';
+
 import { defaultMultisigConfigs } from './multisigIsm.js';
 
 describe('MultisigIsm', () => {
@@ -13,5 +15,25 @@ describe('MultisigIsm', () => {
         );
       }
     });
+
+    it('has a valid number of validators for each threshold', async () => {
+      for (const [chain, config] of Object.entries(defaultMultisigConfigs)) {
+        expect(config.validators.length).to.be.greaterThanOrEqual(
+          config.threshold,
+          `Number of validators for ${chain} is less than the threshold, expected at least ${config.threshold}, got ${config.validators.length}`,
+        );
+      }
+    });
+
+    it('has valid EVM addresses for each validator', async () => {
+      for (const [chain, config] of Object.entries(defaultMultisigConfigs)) {
+        for (const validator of config.validators) {
+          expect(isAddress(validator)).to.equal(
+            true,
+            `Validator address ${validator} for ${chain} is not a valid EVM address`,
+          );
+        }
+      }
+    });
   });
 });