[GH #1366] Issue with copy paste with merge cells

Hi @abhilash.keerampara / @jagadesh.m

I think that I would need a little bit more details here. I tested the latest version (v12.4.0) with merged cells on both sides and do not seem to experience any repetition.

What I did

I created such a dataset in Google sheets

now I pasted it to a non-merged area in Handsontable - and the result is correct as Handsontable does not copy the cell meta (merging) it copies data underneath.

Then I used the merged cell (3, 4) to paste the same data there, and it also works as expected - the merging stays as it was an we get the new data pasted.

Can you share an example/demo with steps to replicate the issue? Do you have any hooks set for the beforePaste / afterPaste or beforeChange / afterChange?