Updated Bar Chart Widget on hover element to display accurate value

[weuceda14]

Description

Onhover element for bar charts was displaying wrong value for certain data. Recalculated how data is populated

Please check if the PR fulfills these requirements

• The commit message follows our guidelines: https://github.com/geosolutions-it/MapStore2/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (check one with "x", remove the others)

• [ x] Bugfix

Issue

What is the current behavior?

#

Barnhart on hover element displays wrong Y value sum for certain data

What is the new behavior?

recalculated how onhover element is populated so now it is accurate for all data types

Breaking change

Does this PR introduce a breaking change? (check one with "x", remove the other)

• Yes, and I documented them in migration notes
• No

Other useful information

[tdipisa]

@weuceda14 thank you so much for contributing to MapStore. We will review as soon as possible.

[offtherailz]

Hi,
Looking at the PR, I'm not able to review these changes.
In order to help us review, can you please specify how to reproduce the issue, including your findings and the explaination of your solution?
Providing the data you used and that produced the issue you mention, or a way to reproduce it with standard data (e.g. us:states), screenshots or everything that can clarify the motivation of this PR, could be very useful to us.

Unit test that proves your fix could be also useful to better understand the logic behind your proposed change, and to prevent the fix from future regressions.