fix: isObject utils fn should return only boolean value (#4756)

### Description
When `isObject` pass with param `null/undefined` it returns
`null/undefined`

We should strict return boolean value
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What's included in this PR?
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### Drive-by changes
```diff
export function isObject(item: any): boolean {
- return item && typeof item === 'object' && !Array.isArray(item);
+ return !!item && typeof item === 'object' && !Array.isArray(item);
}
```
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Are there any minor or drive-by changes also included?
-->

### Related issues

<!--
- Fixes #[issue number here]
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### Backward compatibility

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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
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### Testing
Has updated with test `object.test.ts`
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What kind of testing have these changes undergone?

None/Manual/Unit Tests
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.changeset/quiet-spoons-sleep.md

@@ -0,0 +1,5 @@
+---
+'@hyperlane-xyz/utils': patch
+---
+
+fix: isObject utils fn should return only boolean value

typescript/utils/src/objects.test.ts

@@ -4,6 +4,7 @@ import {
   deepCopy,
   deepEquals,
   diffObjMerge,
+  isObject,
   objMerge,
   objOmit,
 } from './objects.js';
@@ -74,6 +75,14 @@ describe('Object utilities', () => {
     expect(omitted1_2).to.eql({ a: 1, b: { d: 'string' } });
   });
 
+  it('isObject', () => {
+    expect(isObject({})).to.be.true;
+    expect(isObject([])).to.be.false;
+    expect(isObject(null)).to.be.false;
+    expect(isObject(undefined)).to.be.false;
+    expect(isObject(42)).to.be.false;
+  });
+
   describe('diffObjMerge', () => {
     it('should merge objects with equal values', () => {
       const actual = { a: 1, b: 2 };

typescript/utils/src/objects.ts

@@ -5,8 +5,8 @@ import { ethersBigNumberSerializer } from './logging.js';
 import { isNullish } from './typeof.js';
 import { assert } from './validation.js';
 
-export function isObject(item: any) {
-  return item && typeof item === 'object' && !Array.isArray(item);
+export function isObject(item: any): boolean {
+  return !!item && typeof item === 'object' && !Array.isArray(item);
 }
 
 export function deepEquals(v1: any, v2: any) {