Switch to null coalescing operator in Conditionable (#40888)

Author: inxilpro

src/Illuminate/Conditionable/Traits/Conditionable.php

@@ -26,9 +26,9 @@ public function when($value, callable $callback = null, callable $default = null
         }
 
         if ($value) {
-            return $callback($this, $value) ?: $this;
+            return $callback($this, $value) ?? $this;
         } elseif ($default) {
-            return $default($this, $value) ?: $this;
+            return $default($this, $value) ?? $this;
         }
 
         return $this;
@@ -53,9 +53,9 @@ public function unless($value, callable $callback = null, callable $default = nu
         }
 
         if (! $value) {
-            return $callback($this, $value) ?: $this;
+            return $callback($this, $value) ?? $this;
         } elseif ($default) {
-            return $default($this, $value) ?: $this;
+            return $default($this, $value) ?? $this;
         }
 
         return $this;