Well, when I was young and fluent in Geordie and Pitmatic (that's about 85 years ago) 'bubbly' in the sense it is used here in the song, meant someone prone to 'bubble over' i.e. lose their temper easily.

There's another verse I know

Ah thowt ah'd marry a pitman to fill me grate with coal,
But ah have married a keelman an' he's always on the dole,
Ah thowt ah'd marry a Frenchman to love me night and noon,
But ah hev married a keelman. an' mornin's nivvor too soon.