fix map panel not saving correctly in slideshows

[RyanCoulsonCA]

Related Item(s)

#291

Changes

• This PR enables saving for map panels if they're being created in the slideshow editor.
• The ability to change the type of the left side was accidentally removed in a previous PR. I've re-enabled it now.

Testing

Steps:

1. Open the demo page.
2. Create a new slideshow panel and add a map entry.
3. Make some changes to the map and click Save changes at the bottom to add it to the slideshow. The unsaved changes warning should now appear.
4. Save the entire product and ensure the map changes persist.

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This change is 

[github-actions]

Your demo site is ready! 🚀 Visit it here: https://ramp4-pcar4.github.io/storylines-editor/fix-291/#/en/editor

[yileifeng]

Reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @RyanCoulsonCA)

[dnlnashed]

Reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @RyanCoulsonCA)