LF-5026: Duplicate product created when "Save Product" button is clicked twice quickly for specific product names

[SayakaOno]

Description

Disable the "Save product" button in ProductForm while an API call is in progress using the isSaving state.
Regardless of whether the API call succeeds or fails,isSaving is reset to false.

Jira link: https://lite-farm.atlassian.net/browse/LF-5026

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• Passes test case
• UI components visually reviewed on desktop view
• UI components visually reviewed on mobile view
• Other (please explain)

Checklist:

• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• The precommit and linting ran successfully
• I have added or updated language tags for text that's part of the UI
• I have ordered translation keys alphabetically (optional: run pnpm i18n to help with this)
• I have added the GNU General Public License to all new files

[Duncan-Brain]

I was not able to duplicate the selector putting the product into state twice, but the fix looks good for at least the double submission and snackbar.