fdo#74014: More on broadcasting at appropriate places.

Also, call PostDataChanged() to re-paint re-calculated formula cells.

Change-Id: I63161329d4bfe937f754773fd68c37e3836c4950
fdo#74014: Add unit test for pasting an unformatted text into cells.

Change-Id: I87f7b3012a2c139b0ecc3dd699ccecb31af77ac7
fdo#74014: Broadcast changes during undo and redo after paste.

Change-Id: I271bbba5e5eb70e48274a4a062d125456af8ff6c