fix(filesystem): Allow content:// paths to be used in Filesystem.copy()

[BARNZ]

This is my attempt to fix ionic-team/capacitor#6114

Submitting a content:// path to Filesystem.copy such as one provided by @capawesome/capacitor-file-picker plugin would previously result in the application crashing despite the Capacitor filesystem docs stating the following:

Additionally, the Filesystem API supports using full file:// paths, or reading content:// files on Android. Simply leave out the directory param to use a full file path.

This merge requests adds some additional handling when copying from a content:// path:

• Create a temp file
• Resolve and read the content stream to this temp file
• Use this temp file as the source object (so all existing behavior works as usual)
• Clean up this temp file afterwards once the file has been copied

The following example will now work correctly from application code:

Filesystem.copy({
    from: 'content://path/to/some/photo.jpg',
    to: 'Media/myphoto.jpg',
    toDirectory: Directory.External
})

The main reason for doing this is to avoid memory issues when the user picks large files. Native file copying can be used instead of reading the file as base64 over the bridge and writing back to a new path manually.

[abreu1234]

me to need this correction