Update navigation badge to pajamas styling

What does this MR do and why?

Update navigation badge to pajamas styling

• update gl_badge_helper to account for different icon sizes

Changelog: changed

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1. Apply patch
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diff --git a/app/views/layouts/nav/_classification_level_banner.html.haml b/app/views/layouts/nav/_classification_level_banner.html.haml
index f41eadcc0f1..ee52c5308bd 100644
--- a/app/views/layouts/nav/_classification_level_banner.html.haml
+++ b/app/views/layouts/nav/_classification_level_banner.html.haml
@@ -1,3 +1,3 @@
-- if ::Gitlab::ExternalAuthorization.enabled? && @project
+- if true
   = content_for :header_content do
-    = gl_badge_tag(@project.external_authorization_classification_label, { variant: :danger, icon: 'lock-open', icon_size: 8 }, { class: 'has-tooltip', title: s_('ExternalAuthorizationService|Classification label') })
+    = gl_badge_tag('Test Label', { variant: :danger, icon: 'lock-open', icon_size: 8 }, { class: 'has-tooltip', title: s_('ExternalAuthorizationService|Classification label') })

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• I have evaluated the MR acceptance checklist for this MR.

Related to #344406 (closed)