[BUG] Area chart does not show Split series aggregation label

[huyaboo]

Describe the bug

In OSD 2.13, if an area chart were created with a Split chart Filters aggregation with a label containing the character -, the Split series Term aggregation label will not show.

To Reproduce
Steps to reproduce the behavior:

1. Add sample data (ecommerce)
2. Create an Area Visualization
3. Under Buckets, create a Split chart with the following:
   • Aggregation: Filters
   • Filter 1: currency: EUR
   • Filter 1 label: -
   • Do not add another filter
4. Under Buckets, create a Split series with the following:
   • Sub aggregation: Terms
   • Field: customer_first_name.keyword
   • Order by: Metric: Count
   • Order: Descending
   • Toggle on Group other values in separate bucket
   • Custom label: Other
5. Clicking update does not show the Other label

Expected behavior
Using the - character as a filter label should not hide the split series label.

OpenSearch Version
2.13

Dashboards Version
2.13

Plugins

Screenshots

Screen.Recording.2024-08-14.at.9.15.52.AM.mov

Host/Environment (please complete the following information):

• OS: MacOS
• Browser and version: Firefox

Additional context

Add any other context about the problem here.

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