Fix views preview when pattern declared by ui_pattern_library in the front theme.

[DuaelFr]

Without the provider, views cannot find the pattern template so the preview Ajax request throws an error 500.
With the provider, the pattern is used as expected.

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Configuration:

• my pattern is declared in my frontend theme
• it is used by a content type view mode via ui_patterns_layouts and field_layouts
• the view list content of this type and display theme using this view mode

[mika2na]

Moved to Drupal.org https://www.drupal.org/project/ui_patterns/issues/3314789