Ensure config defaults for saving and loading match

[ZeroErrors]

Description:

Previously config with no changes would be saved with some fields. That is because some config wasn't using the same default for loading and saving.

For example the first time you load dash and save the config it would create a file like so:

[General]
quick_view=none

[Camera]
auto_reconnect_time_secs=6

[Vehicle]
plugin=unloader

With the changes in this PR when there has been no config values changed then no config file is saved to disk so the defaults will continue to be used.

Checklist:

• [x] The code change is tested and works locally.