Add Custom Color Selection for Color Scale in Table Chart

[UmakanthKaspa]

Description

The 'Show Color Scale' feature in the Table Chart currently defaults to a single color. This lacks flexibility for users who might prefer custom colors or gradients. Add options to allow selecting custom colors for better visualization and alignment with user preferences.

Proposed Solution

• Add a color picker for users to choose a custom color.
• Provide an option to switch to gradient mode, allowing the selection of start and end colors.