Connector generator: clean body shape to avoid multiple segments

Previously, generic connector generator would create multiple segments for a given line.

This confuses the silkscreen generation logic, creating some weird effects like:

(Above image is Wago_722-832_1x02_P7.5mm_Horizontal from !928 )

This MR adds a clean shape pass at the end of body shape generation to join those segments in a straight line.

With this MR, the same footprint looks like: