fix: getAllTokens initialization fix (#29488)

## Description
useState is calling the initialisation function unnecessarily for every
render, We will call it only during state initialisation.
#### PR fixes following issue(s)
Fixes #29491
#### Type of change
- Bug fix (non-breaking change which fixes an issue)
## Testing
>
#### How Has This Been Tested?
> Please describe the tests that you ran to verify your changes. Also
list any relevant details for your test configuration.
> Delete anything that is not relevant
- [ ] Manual
- [ ] JUnit
- [ ] Jest
- [ ] Cypress
>
>
#### Test Plan
> Add Testsmith test cases links that relate to this PR
>
>
#### Issues raised during DP testing
> Link issues raised during DP testing for better visiblity and tracking
(copy link from comments dropped on this PR)
>
>
>
## Checklist:
#### Dev activity
- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my own code
- [x] I have commented my code, particularly in hard-to-understand areas
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] PR is being merged under a feature flag


#### QA activity:
- [ ] [Speedbreak
features](https://github.com/appsmithorg/TestSmith/wiki/Guidelines-for-test-plans#speedbreakers-)
have been covered
- [ ] Test plan covers all impacted features and [areas of
interest](https://github.com/appsmithorg/TestSmith/wiki/Guidelines-for-test-plans#areas-of-interest-)
- [ ] Test plan has been peer reviewed by project stakeholders and other
QA members
- [ ] Manually tested functionality on DP
- [ ] We had an implementation alignment call with stakeholders post QA
Round 2
- [ ] Cypress test cases have been added and approved by SDET/manual QA
- [ ] Added `Test Plan Approved` label after Cypress tests were reviewed
- [ ] Added `Test Plan Approved` label after JUnit tests were reviewed


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **Tests**
- Improved stability of list widget server-side pagination tests by
introducing wait times.

- **Refactor**
- Optimized theme state initialization in `useTheme` to enhance
performance.

- **Bug Fixes**
- Adjusted handling of moment objects in evaluation workers to ensure
accurate serialization of updates.

- **Documentation**
- Updated test documentation to reflect changes in moment object
handling and serialization.

(Note: Duplicate entries for `useTheme` have been consolidated in the
Refactor category to maintain clarity and avoid repetition.)
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

app/client/packages/design-system/theming/src/hooks/src/useTheme.tsx

@@ -44,7 +44,7 @@ export function useTheme(props: UseThemeProps = {}) {
     userSizing,
   );
 
-  const [theme, setTheme] = useState(tokensAccessor.getAllTokens());
+  const [theme, setTheme] = useState(tokensAccessor.getAllTokens);
 
   useEffect(() => {
     if (colorMode) {