Reviewing currently set flags

Currently, in https://github.com/flathub/dev.vencord.Vesktop/blob/master/startvesktop a decent amount of flags are set.
Of those however, most (if not all) of them seem to be deprecated.

At least 3 we no longer need (as covered in: https://github.com/flathub/dev.vencord.Vesktop/pull/75) are:
* ozone-platform
* enable-wayland-ime
* wayland-text-input-version

Though we very well may need it, we should consider if we truly need this flag.
* disable-gpu-sandbox

As disabling sandboxing of the gpu has... troubling security implications. Furthermore such a flag cannot be found in https://source.chromium.org/chromium/chromium/src/+/main:chrome/browser/flag-metadata.json

Finally, there is no mention of the following flag in https://www.electronjs.org/docs/latest/api/command-line-switches and https://source.chromium.org/chromium/chromium/src/+/main:chrome/browser/flag-metadata.json
* enable-speech-dispatcher

Therefore we MAY be able to disable of these flags, most if not all.