Plugin "registerVideoField" with type:"multiselect"

### Describe the problem to be solved

I would like to submit a feature request regarding a limitation in plugin development when using the "registerVideoField" function. Currently, only a single selection is allowed using the "select" type. However, I would like to have the ability to enable multiple selections by incorporating a "multiselect" option.

### Describe the solution you would like

I would like to request the addition of support for a "multiselect" option within the "registerVideoField" functionality, allowing users to select multiple options simultaneously.

Start by locating the registerVideoField entry point and the existing handling for the select type. Trace how registered video fields render and store their selected values, then verify that a multiselect option allows multiple selections without changing existing select behavior.

Written by the indexing model from the issue text.