Add an "extra_gated_fields" supported field-type (textarea)

[tobiapoppi]

Problem Description:
We are trying to release our dataset on HF platform, and given that the dataset contains sensitive data, we want to employ the Gated Dataset by using the "extra-gated-prompt" and "extra-gated-fields" in the metadata of the Dataset Card.
The main problem is that we want to ask the user a detailed explanation about the intended usage of the dataset.

Requested Feature:
To do so, a bigger text-area would be more suitable than a simple textline box.

Additional context:
How the textline is now visualized:

Here's our metadata example:

---
extra_gated_prompt: >-
  WARNING! This dataset contains explicit sexual content, racially insensitive
  language, and other material that may be disturbing or harmful to certain
  users.
extra_gated_fields:
  Institutional E-mail address:
    type: text
  Country:
    type: country

  # THIS IS THE FIELD FOR WHICH WE WOULD PREFER TO USE A TEXT-AREA
  Detailed Use Description (please, provide a detailed description of how you intend to use this dataset):
    type: text

  I declare to use this dataset for non-commercial use ONLY:
    type: checkbox
  I assume all responsibility for any consequences that may arise from the misuse of this dataset and I release the authors of the dataset from any liability:
    type: checkbox

extra_gated_heading: "By submitting this form, you confirm that you have read and agree to all the above conditions. Access to the dataset will only be granted to users with verified institutional addresses for research purposes and non-malicious use only."
extra_gated_button_content: "Submit"
---

[julien-c]

yep, sounds reasonable to expose a bit more control, wdyt @SBrandeis?

[julien-c]

thanks for opening this @tobiapoppi