[FEAT]Resolve Theme Switching Issues in Admin Dashboard

[DemDem-code]

## Description

Switching between light and dark themes in the admin dashboard is inconsistent, with the selected theme sometimes not applying correctly. This issue disrupts the user experience and undermines the customizable nature of the dashboard.

Purpose:
To ensure that theme switching in the admin dashboard works reliably, providing users with a consistent and customizable interface that reflects their preferences.

Acceptance Criteria:

Theme switching between light and dark modes works consistently.
The selected theme is applied immediately and remains active across sessions.
No visual glitches occur during theme transitions.
User preferences for themes are correctly saved and recalled.
Testing confirms stable theme functionality across all supported browsers.

Requirements:

Investigate the current theme-switching logic and identify inconsistencies.
Refactor code to ensure reliable application of selected themes.
Test theme switching across various scenarios (e.g., different browsers, sessions).
Address any visual or functional issues discovered during testing.
Update user guides and documentation to reflect reliable theme-switching functionality.

Expected Outcome:
Theme switching in the admin dashboard will be consistent and reliable, enhancing user satisfaction by allowing for a personalized and stable interface.