Merge branch '4.3' into 4.4

* 4.3:
  Fix inconsistent return points.
  pass translation parameters to the trans filter
  [Mime] fixed wrong mimetype
  [ProxyManagerBridge] Polyfill for unmaintained version
  [HttpClient] Declare `$active` first to prevent weird issue
  Remove deprecated assertContains
  [HttpClient] fix tests
  SCA: dropped unused mocks, duplicate import and a function alias usage
  Added correct plural for box -> boxes
  [Config] fix test
  Fix remaining tests
  Improve fa (persian) translation

Author: nicolas-grekas

FormFieldRegistry.php

@@ -57,7 +57,7 @@ public function remove($name)
         $target = &$this->fields;
         while (\count($segments) > 1) {
             $path = array_shift($segments);
-            if (!\array_key_exists($path, $target)) {
+            if (!\is_array($target) || !\array_key_exists($path, $target)) {
                 return;
             }
             $target = &$target[$path];
@@ -80,7 +80,7 @@ public function &get($name)
         $target = &$this->fields;
         while ($segments) {
             $path = array_shift($segments);
-            if (!\array_key_exists($path, $target)) {
+            if (!\is_array($target) || !\array_key_exists($path, $target)) {
                 throw new \InvalidArgumentException(sprintf('Unreachable field "%s"', $path));
             }
             $target = &$target[$path];