fix saving on metadata page

[RyanCoulsonCA]

Related Item(s)

#276

Changes

• This PR fixes the saving issue with the metadata page. It will set unsavedChanges to true if any changes have been made to the metadata.

Testing

Steps:

1. Load a product.
2. Make some changes to the metadata on the metadata page.
3. Click next to get to the main editor. The unsaved changes warning should appear at the top.
4. Ensure that the changes you've made to the metadata 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-276/#/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)

[KashishMistry]

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

[szczz]

Reviewed 1 of 2 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @RyanCoulsonCA)