Upgrade OkHttp to 4.12.

Addresses #13491

libsignal-service/src/main/java/org/whispersystems/signalservice/internal/push/http/DigestingRequestBody.kt

@@ -1,8 +1,8 @@
 package org.whispersystems.signalservice.internal.push.http
 
 import okhttp3.MediaType
+import okhttp3.MediaType.Companion.toMediaTypeOrNull
 import okhttp3.RequestBody
-import okhttp3.internal.http.UnrepeatableRequestBody
 import okio.BufferedSink
 import org.signal.libsignal.protocol.incrementalmac.ChunkSizeChoice
 import org.signal.libsignal.protocol.logging.Log
@@ -26,7 +26,7 @@ class DigestingRequestBody(
   private val progressListener: SignalServiceAttachment.ProgressListener?,
   private val cancelationSignal: CancelationSignal?,
   private val contentStart: Long
-) : RequestBody(), UnrepeatableRequestBody {
+) : RequestBody() {
   var attachmentDigest: AttachmentDigest? = null
 
   init {
@@ -35,7 +35,7 @@ class DigestingRequestBody(
   }
 
   override fun contentType(): MediaType? {
-    return MediaType.parse(contentType)
+    return contentType.toMediaTypeOrNull()
   }
 
   @Throws(IOException::class)
@@ -85,6 +85,10 @@ class DigestingRequestBody(
     return if (contentLength > 0) contentLength - contentStart else -1
   }
 
+  override fun isOneShot(): Boolean {
+    return true
+  }
+
   private fun logMessage(actual: Long, expected: Long): String {
     val difference = actual - expected
     return if (difference > 0) {