Button group component selected value type inconsistency with multi-selection

[GrowwithNaveen]

Description
Inconsistency in the data type of the selected value returned by the button group component when used with the "Enable multiple selection" feature.

Current behavior:

• When "Enable multiple selection" is disabled and a single button is clicked within the group while dragging on the canvas, the selected value is an integer representing the index of the clicked button.
• When "Enable multiple selection" is enabled and multiple buttons are selected within the group while dragging on the canvas, the selected value becomes a string containing a comma-separated list of button indices.

Expected behavior:
The data type of the selected value should remain consistent regardless of the "Enable multiple selection" setting. Ideally:

• If a single button is selected (regardless of the multi-selection setting), the selected value should be an integer representing the button's index.
• If multiple buttons are selected (with multi-selection enabled), the selected value should be an array containing the indices of the selected buttons.

Steps to reproduce:
Please find the below video grab,

Screen.Recording.2024-05-08.at.11.39.08.PM.mov

Note
This was the behavior from initial phase, so there might be users using this. Check for the backward compatibility exhaustively.