TB 34439 [android]: Isolate Icon loader on Android.

Originally, android-components#34439.

mobile/android/android-components/components/browser/engine-gecko/src/main/java/mozilla/components/browser/engine/gecko/fetch/GeckoViewFetchClient.kt

@@ -89,6 +89,7 @@ private fun Request.toWebRequest(): WebRequest = WebRequest.Builder(url)
     .referrer(referrerUrl)
     .cacheMode(if (useCaches) CACHE_MODE_DEFAULT else CACHE_MODE_RELOAD)
     .beConservative(conservative)
+    .origin(origin)
     .build()
 
 private fun WebRequest.Builder.addHeadersFrom(request: Request): WebRequest.Builder {

mobile/android/android-components/components/browser/icons/src/main/java/mozilla/components/browser/icons/loader/HttpIconLoader.kt

@@ -62,6 +62,7 @@ open class HttpIconLoader(
             redirect = Request.Redirect.FOLLOW,
             useCaches = true,
             private = request.isPrivate,
+            origin = request.url
         )
 
         return try {

mobile/android/android-components/components/concept/fetch/src/main/java/mozilla/components/concept/fetch/Request.kt

@@ -49,6 +49,7 @@ data class Request(
     val cookiePolicy: CookiePolicy = CookiePolicy.INCLUDE,
     val useCaches: Boolean = true,
     val private: Boolean = false,
+    val origin: String? = null,
 ) {
     var referrerUrl: String? = null
     var conservative: Boolean = false