Replace TWIG render with is not empty checks

Problem/Motivation

Currently the Bootstrap Paragraphs use a lot of TWIG render to identify if a field has content or not. This could be simplified by using is not empty checks in TWIG templates.

Steps to reproduce

Proposed resolution

Replace TWIG |render with is not empty checks based on paragraph entity instead of content render object.

Current code with TWIG render based on content render object:

{% set background_field = content.bp_background|render %}
{% if background_field %}
  {% set classes = classes|merge(column_style_2_classes) %}
{% endif %}

Refactored with TWIG is empty check based on paragraph entity:

{% if paragraph.bp_column_style_2 is not empty %}
  {% set classes = classes|merge(column_style_2_classes) %}
{% endif %}

• Improve performance because fields are not rendered twice or more during TWIG templating.
• Cleaner code structure.

Remaining tasks

User interface changes

API changes

Data model changes