[FW][FIX] Charts: Fix tooltip value when data is zero

[fw-bot]

Following a refactoring of the charts, the tooltip would not display the data value when the data equalled zero.

How to reproduce:

• generate a line graph such that one of the dataset points is 0
• Hover the said data point

-> the tooltip will read something along "Series 1:" and no value afterwards.

Task: 4251681

Description:

description of this task, what is implemented and why it is implemented that way.

Task: TASK_ID

review checklist

• feature is organized in plugin, or UI components
• support of duplicate sheet (deep copy)
• in model/core: ranges are Range object, and can be adapted (adaptRanges)
• in model/UI: ranges are strings (to show the user)
• undo-able commands (uses this.history.update)
• multiuser-able commands (has inverse commands and transformations where needed)
• new/updated/removed commands are documented
• exportable in excel
• translations (_t("qmsdf %s", abc))
• unit tested
• clean commented code
• track breaking changes
• doc is rebuild (npm run doc)
• status is correct in Odoo

Forward-Port-Of: #5094

[robodoo]

[fw-bot]

@rrahir @pro-odoo cherrypicking of pull request #5094 failed.

stdout:

Auto-merging src/helpers/figures/charts/chart_ui_common.ts
Auto-merging tests/figures/chart/chart_plugin.test.ts
CONFLICT (content): Merge conflict in tests/figures/chart/chart_plugin.test.ts

Either perform the forward-port manually (and push to this branch, proceeding as usual) or close this PR (maybe?).

In the former case, you may want to edit this PR message as well.

⚠️ after resolving this conflict, you will need to merge it via @robodoo.

More info at https://github.com/odoo/odoo/wiki/Mergebot#forward-port

[pro-odoo]

robodoo r+