Renaming a Symbol Adds Secondary Theme to Scene Symbol List

[b-camphart]

Is there an existing issue for this?

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✍️ Description

When you rename a symbol with the Scene Symbol tool open, a second copy of the theme is added to the list of available themes.

🔬 Minimal Reproduction

1. Start a new project
2. Create theme named "Growing Up"
3. Create a symbol named "The Ring" in the "Growing Up" theme
4. Create a scene named "Frank Dies"
5. Open the scene symbols tool for the "Frank Dies" scene
6. Rename the "The Ring" symbol in the "Growing Up" theme to "Two Rings"
7. Click on the "Pin Symbol" button in the scene symbols tool

Expected Result

The "Growing Up" theme should be listed once with a single "Two Rings" symbol available

Actual Result

The "Growing Up" theme is listed twice.

Relevant log output

No response

Anything else?

No response