fix(bi): prevent stacked charts from showing multiple y axes

[EDsCODE]

Problem

• when stacked charts are used, multiple Y axes appear

Changes

• the plugin uses the default "y" axis setting. Make sure this is respected

Before:

After:

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Does this work well for both Cloud and self-hosted?

How did you test this code?

[github-actions]

Size Change: 0 B

Total Size: 1.13 MB

ℹ️ View Unchanged

Filename	Size
frontend/dist/toolbar.js	1.13 MB

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