[FIX] charts: crash when converting empty chart to scorecard/gauge

[dhrp-odoo]

Description:

When creating a Scorecard or Gauge from an empty carousel/chart, context.range can be an empty array. Accessing context.range[0].dataRange crashed.

This PR adds a check to ensure that context.range has at least one element before accessing context.range[0].dataRange.

Task: 5181741

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

[robodoo]