Improve toKilobytes to handle spaces and case-insensitive units (#55019)

* Improve `toKilobytes` to handle spaces and case-insensitive units in File rule validation

* Update File.php

---------

Co-authored-by: Taylor Otwell <[email protected]>

Author: alikhosravidev

src/Illuminate/Validation/Rules/File.php

@@ -217,6 +217,8 @@ protected function toKilobytes($size)
             return $size;
         }
 
+        $size = strtolower(trim($size));
+
         $value = floatval($size);
 
         return round(match (true) {

tests/Validation/ValidationFileRuleTest.php

@@ -418,6 +418,27 @@ public function testItCanSetDefaultUsing()
         );
     }
 
+    public function testFileSizeConversionWithDifferentUnits()
+    {
+        $this->passes(
+            File::image()->size('5MB'),
+            UploadedFile::fake()->create('foo.png', 5000)
+        );
+
+        $this->passes(
+            File::image()->size(' 2gb '),
+            UploadedFile::fake()->create('foo.png', 2 * 1000000)
+        );
+
+        $this->passes(
+            File::image()->size('1Tb'),
+            UploadedFile::fake()->create('foo.png', 1000000000)
+        );
+
+        $this->expectException(\InvalidArgumentException::class);
+        File::image()->size('10xyz');
+    }
+
     protected function setUp(): void
     {
         $container = Container::getInstance();