LogViewerActivity: don't crash if pipe closes

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

ui/src/main/java/com/wireguard/android/activity/LogViewerActivity.kt

@@ -346,7 +346,10 @@ class LogViewerActivity : AppCompatActivity() {
             if (mode != "r") return null
             val log = logForUri(uri) ?: return null
             return openPipeHelper(uri, "text/plain", null, log) { output, _, _, _, l ->
+                try {
                     FileOutputStream(output.fileDescriptor).write(l!!)
+                } catch (_: Exception) {
+                }
             }
         }
     }