Adjust position of hover label on Elevation Profile widget

[andrewdc_tt]

There is an issue where in some situations, the hover popup shown on mouseover covers up the elevation profile widget chart, making it difficult to determine on the chart where the value comes from. 

In most cases the popup is a bit more intellegent in its position, however in this example it is not (and is in fact offset from where the cursor should be).

[AlixVezina]

Hi @andrewdc_tt ! Are you seeing this issue all the time, or do you observe a pattern with a specific elevation layer used as reference?

[andrewdc_tt]

@AlixVezina this was reported by one of our app users. From what I can tell it only happens sometimes,  seems to be when the profile chart line hits a particular angle - a differently drawn line might be fine within the same elevation source.