Button via "Link / Button" plugin is Not Button by Default

[wesleyboar]

Is your feature request related to a problem? Please describe.
When creating a "Button" via Bootstrap4 "Link / Button" plugin, element should look like a button (but user must set "Type" to see button).

Link type	Type

Describe the solution you'd like
Ideas:

• A. User is forced to choose type.
  ^{⚠️ But forcing choice for Link type of "Link" is unnecessary.}
• B. Form sets type dynamically.
  ^{⚠️ But what if user already made correct "Type" choice before changing "Link type"?}

Describe alternatives you've considered
Editor always must choose "Type", but won't know that unless they see link (set as "Button") does not look like a button, or have learned already to set "Type".

Additional context
Solution proposed by AI, which could be integrated into bootstrap4_link/extend.py, is to require the field:

from django import forms
from djangocms_bootstrap4.contrib.bootstrap4_link.models import Bootstrap4Link

class Bootstrap4LinkForm(forms.ModelForm):
    class Meta:
        model = Bootstrap4Link
        fields = "__all__"

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        # example: make link_context and link_size optional
        self.fields["link_context"].required = False
        self.fields["link_size"].required = False

Important

How to prevent "Primary" being set for Links? It is okay if it is (CSS supports it), but it is unnecessary.