feat: Don't make unecesary writes to disk for pinned tabs, b=no-bug, c=tabs

Author: mr-cheffy

src/zen/tabs/ZenPinnedTabManager.mjs

@@ -778,6 +778,10 @@
         return;
       }
       const existingPin = this._pinsCache.find((p) => p.uuid === pin.uuid);
+      if (existingPin && existingPin === pin) {
+        // We want to avoid unnecessary writes
+        return;
+      }
       if (existingPin) {
         Object.assign(existingPin, pin);
       } else {