Remove max line limit from footer summary on TV

It's [1] applied to TV. Under larger font sizes, it may reach the max line limit for the footer summary on the "Unused apps" page which would cut it off. As the footer is several lines, we use the SettingsLib FooterPreference
instead of the default preference class.

Bug: 220584404
[1]: I856d2e3e00ff873a85609625070f6ed81e77ff98
Test: reproduce with different font sizes, line is not cut off

Change-Id: I6a4ad0926a8a53869c44c813f4975c3a6634742e