[WIP] Add default content to rich text in HubSpot template

[Copilot]

Thanks for asking me to work on this. I will get started on it and keep this PR's description up to date as I form a plan and make progress.

Original prompt

Hubspot template:
How should I put the rich text content in my template so that I have default content inside it?
{% dnd_area "main_content" label="Left side content" %}
{% dnd_section %}
{% dnd_module "left_side" path="@hubspot/rich_text", label="Left side content" %}

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