Fixed download animation when tabs are on the right

src/zen/downloads/ZenDownloadAnimation.mjs

@@ -317,7 +317,6 @@
           `;
 
         const sideProp = areTabsPositionedRight ? 'right' : 'left';
-        const startSideValue = areTabsPositionedRight ? '50px' : '-50px';
 
         const fragment = window.MozXULElement.parseXULToFragment(boxAnimationHTML);
         this.#boxAnimationElement = fragment.querySelector('.zen-download-box-animation');
@@ -325,7 +324,7 @@
         Object.assign(this.#boxAnimationElement.style, {
           bottom: '24px',
           transform: 'scale(0.8)',
-          [sideProp]: startSideValue,
+          [sideProp]: '-50px',
         });
 
         wrapper.appendChild(this.#boxAnimationElement);