accept also one cell chart ranges for external data provider, fdo#79772

Change-Id: I2078205b0aecdea13e342c4a625b82a70df0fb4f
remove comments

Change-Id: I674e1443ce4e856206eeec7ea62083fcf0422f51
XY chart needs to set the X value property

Change-Id: Ib17b564c187dfec8abb7a17b2602f814362dd34f