fix(ui): add missing preloader for the pricing page (#142)

Description

Pricing page is missing a preloader when fetching data for the table.

Related issue

#142 (closed)

Examples

Checklist

• the MR description has been reviewed
• this MR contains text changes and they have been reviewed OR there are no texts changes
• this MR contains GUI/CLI changes and they have been reviewed OR there are no GUI/CLI changes
• this MR contains API changes and they have been reviewed OR there are no API changes

Closes #142 (closed)