Browsing Maori translation

Update the "seconds" label so that it always has the correct singular/plural form
Translators: label for the seconds selector in the "Skip to" dialogue

Fix the label width at the maximum necessary for the plural labels, to prevent it changing size when we change the spinner value
Translators: you should translate this string to a number (written in digits) which corresponds to the longer character length of the
* translations for "second" and "seconds", as translated elsewhere in this file. For example, in English, "second" is 6 characters long and
* "seconds" is 7 characters long, so this string should be translated to "7". See: bgo#639398