[LiveComponent] Fix race condition with inputs being modified during a request

[tijnema]

Q	A
Bug fix?	yes
New feature?	no
Deprecations?	no
Documentation?	no
Issues	Fix #2899
License	MIT

As discussed in issue #2899, sometimes form inputs would be cleared. This appears to be a race condition where the input was not sent to the server, but the server response would override the input if it had been modified between request start and morph, even if the server didn't modify anything.

This fixes the issue by checking if an input value is different between now and the value sent to the server, and will then not update the value from the server. Server side changes are still supported, because the code will automatically send a new request for the changed input.

I tried writing a test for it, but so far couldn't reproduce it with a test

[github-actions]

📊 Packages dist files size difference

Thanks for the PR! Here is the difference in size of the packages dist files between the base branch and the PR.
Please review the changes and make sure they are expected.

File	Before (Size / Gzip)	After (Size / Gzip)
LiveComponent
live_controller.d.ts	7.96 kB / 1.96 kB	7.99 kB0% / 1.96 kB0%
live_controller.js	99.07 kB / 21.35 kB	100.16 kB+1% 📈 / 21.55 kB+1% 📈