Update Sample Data Page UI for New Updated UX

[wanglam]

Is your feature request related to a problem? Please describe.

The current UI of the Sample Data page does not align with the updated UX design patterns in OpenSearch Dashboards. The data source selector is not positioned correctly, and there is a duplicate title for the Sample Data section.

Describe the solution you'd like

The proposed solution includes the following changes:

1. Move the data source selector to the top right corner of the page, aligning it with other pages in the updated UX.
2. Remove the duplicate "Sample Data" title from the page.
   These changes will improve the consistency and visual appeal of the Sample Data page, making it conform to the updated UX guidelines.

Describe alternatives you've considered
N/A

Additional context
N/A