[Backport to 2.3-develop] Changed constructor typo in Javascript class

[dverkade]

Backport of #11933

Original PR:

Changed variable with typo consturctor to constructor

This was already solved in the 2.3 develop branch, but another commit with a typo was also in the given PR. This was not yet present in de 2.3 develop branch, so backported the original PR to the 2.3 develop branch.

[orlangur]

Reminder: cherry-pick 33c476e also

[dverkade]

@orlangur That's exactly what I did, cherry pick 33c476e since that commit had changes in it which where not present in the 2.3-develop branch. This resulted in a merge conflict which I have resolved, keeping the changes in the 2.3-develop branch and adding the other typo which was fixed in that commit.

[orlangur]

@dverkade, oh, I see, you tried to do a squashed merge of your previous PR and there was a conflict due to #10755. Thanks for porting properly! I was confused by a less amount of changes.