Apply suggestion:

- Added `MediaSource.safeUrl` property replacing `withCleanUrl` method.
- Made `url` private so it can't be used externally.
- Reverted code in `CoilMediaFetcher`
- Also add tests

libraries/voiceplayer/impl/src/main/kotlin/io/element/android/libraries/voiceplayer/impl/VoiceMessageMediaRepo.kt

@@ -95,7 +95,7 @@ class DefaultVoiceMessageMediaRepo(
         }
     }
 
-    private val cachedFile: File? = mxcTools.mxcUri2FilePath(mediaSource.url)?.let {
+    private val cachedFile: File? = mxcTools.mxcUri2FilePath(mediaSource.safeUrl)?.let {
         File("${cacheDir.path}/$CACHE_VOICE_SUBDIR/$it")
     }
 }