Enable cert bundle autodetction by default

Arch Linux's ffmpeg package recently switched to mbedtls. This results
in the bundle path needing to be explicitly passed to mpv else
verification will always fail.

https://gitlab.archlinux.org/archlinux/packaging/packages/ffmpeg/-/issues/10

resources/settings/settings_description.json

@@ -144,7 +144,7 @@
         "value": "autodetectCertBundle",
         "display_name": "Auto-Detect Certificate Bundle",
         "help": "Allows use of system certificates for TLS.",
-        "default": false,
+        "default": true,
         "platforms": [ "linux" ]
       },
       {