container: Quote arguments that contain spaces when restoring pytest args

Adds single quotes inside single-quoted string, for example bash command echo ' '"'"'test'"'"' ' prints 'test'.

Also:

• Remove wrong comment in the same function.
• Fix quote usages in container script.

Tested that running bepasty tests with keyword expression filter -k "enable_disable or uninstall works.

Signed-off-by: Veiko Aasa veiko17@disroot.org