Remove License#contentUri

It seems to not be used anywhere.

app/src/main/java/org/schabi/newpipe/about/License.kt

@@ -1,6 +1,5 @@
 package org.schabi.newpipe.about
 
-import android.net.Uri
 import android.os.Parcelable
 import kotlinx.android.parcel.Parcelize
 import java.io.Serializable
@@ -9,11 +8,4 @@ import java.io.Serializable
  * Class for storing information about a software license.
  */
 @Parcelize
-class License(val name: String, val abbreviation: String, val filename: String) : Parcelable, Serializable {
-    val contentUri: Uri
-        get() = Uri.Builder()
-            .scheme("file")
-            .path("/android_asset")
-            .appendPath(filename)
-            .build()
-}
+class License(val name: String, val abbreviation: String, val filename: String) : Parcelable, Serializable