Migrate HeaderUtil to Kotlin (#48676)

Summary:
Migrate `HeaderUtil` to Kotlin.

## Changelog:

[INTERNAL] - Migrate `HeaderUtil` to Kotlin

Pull Request resolved: https://github.com/facebook/react-native/pull/48676

Test Plan:
The file had tests:

```bash
yarn test-android
```

Reviewed By: fabriziocucci

Differential Revision: D68205283

Pulled By: javache

fbshipit-source-id: 23ad7726a5e597d5012eec6b194af3b1e10a8b7a

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/modules/network/HeaderUtil.kt

@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-package com.facebook.react.modules.network;
+package com.facebook.react.modules.network
 
 /**
  * The class purpose is to weaken too strict OkHttp restriction on http headers. See:
@@ -13,19 +13,21 @@ package com.facebook.react.modules.network;
  * information. It is better to get 401 from the server in this case, rather than non descriptive
  * error as 401 could be handled to invalidate the wrong token in the client code.
  */
-class HeaderUtil {
-
-  public static String stripHeaderName(String name) {
-    StringBuilder builder = new StringBuilder(name.length());
-    boolean modified = false;
-    for (int i = 0, length = name.length(); i < length; i++) {
-      char c = name.charAt(i);
-      if (c > '\u0020' && c < '\u007f') {
-        builder.append(c);
-      } else {
-        modified = true;
+internal class HeaderUtil {
+  public companion object {
+    @JvmStatic
+    public fun stripHeaderName(name: String): String {
+      val builder = StringBuilder(name.length)
+      var modified = false
+      for (i in 0 until name.length) {
+        val c = name[i]
+        if (c > '\u0020' && c < '\u007f') {
+          builder.append(c)
+        } else {
+          modified = true
+        }
       }
+      return if (modified) builder.toString() else name
     }
-    return modified ? builder.toString() : name;
   }
 }