Currently, if Night Color is set to Always off in the KCM, clicking the applet says Night color was turned on but nothing happens. Instead, bring the user to the KCM so they can enable it there first. The bug report asks for enabling it when clicking, but since we don't know what settings the user wants it's better to take them to the settings page. I also changed the tooltip to make it clear what clicking the icon will do.
This MR also fixes a small bug, where if Night Color is enabled but inhibited, and then the user sets it to Always off in the KCM, the tooltip would still say it was inhibited. Now the inhibition tooltip will only appear if Night Color is actually turned on, otherwise, it will show the tooltip to open the Night Color KCM. (line 34)
This is my first actual code change ever. Please help me if you find something wrong. :)