Update uui-tab.element.ts

Unintentional change - not sure why the 14 went to 15.

Author: jonnymuir

packages/uui-tabs/lib/uui-tab.element.ts

@@ -184,7 +184,7 @@ export class UUITabElement extends ActiveMixin(LabelMixin('', LitElement)) {
         right: auto;
         border-radius: var(--uui-border-radius) var(--uui-border-radius) 0 0;
         height: 0px;
-        width: calc(100% - 15px);
+        width: calc(100% - 14px);
         bottom: 0;
         transition:
           opacity linear 120ms,