Remove 128-character limit on remote-video captions and descriptions

Problem/Motivation

Custom remote-video captions and descriptions are limited to 128 characters by Drupal's textfield default. This is too short for captions combining several tokens.

Steps to reproduce

1. Open the GLightbox Media Remote Video formatter settings on a media type's Manage display page.
2. Select Custom (with tokens) for Caption or Caption description.
3. Try to enter text or a token pattern longer than 128 characters.

Proposed resolution

Use textareas for both settings, allowing longer captions and token patterns. Stored values remain strings.

The equivalent proposal for the main Glightbox module is #3628610.

Local testing

With the locally prepared change, browser checks on Drupal 11.4.8 confirm both inputs retain 740 characters in display and Views-style forms.

Remaining tasks

Review the MR (verify saving, reopening and rendering longer captions and descriptions) then merge MR.