[FIX] theme_enark: set a real boolean value to btn-outline-primary

For each theme, there are files redefining the different website SCSS
variables, in order for the color palettes, fonts, buttons,... to have
the styles defined by them. These redefinitions are also used by the
"Theme Options", to show the current values in the different widgets.

In order for the primary buttons to be "outlined", the "Enark" theme set
the `btn-primary-outline` variable to `'true'`. However, this value
should be a boolean instead of a string. Indeed, since the option does
not recognize the string value, the "Buttons Primary Style" widget
therefore shows a "/" instead of "Outline", which is not correct.

This commit fixes this by setting a boolean value.

opw-3957157

closes odoo/design-themes#814

X-original-commit: 14ff983da2
Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

theme_enark/static/src/scss/primary_variables.scss

@@ -143,7 +143,7 @@ $o-website-values-palettes: (
         'buttons-font':         'Bitter',
         'footer-template':      'descriptive',
         'header-links-style':   'outline',
-        'btn-primary-outline':  'true',
+        'btn-primary-outline':  true,
     ),
 );