fix(button link): remove text decoration (#2190)

Author: yggg

src/framework/theme/components/button/_button.component.theme.scss

@@ -54,6 +54,10 @@
     }
   }
 
+  a[nbButton] {
+    text-decoration: none;
+  }
+
   @include button-filled;
   @include button-outline;
   @include button-ghost;

src/framework/theme/components/button/button.component.scss

@@ -9,7 +9,6 @@
 :host {
   appearance: none;
   text-align: center;
-  text-decoration: none;
   display: inline-flex;
   align-items: center;
   justify-content: center;