Update sqlite3_web package

[simolus3]

This updates sqlite3_web to the latest version, 0.8.0. That version avoids representing URLs as Dart Uri to reduce the size of database workers (using Uri.parse pulls in a lot of code). Additionally, it allows using a compile-time option to disable support for Dart BigInts (which don't use JS BigInts internally, and also pull a bit of code). For the worker, we can just rely on JS BigInts since that's how clients encode those values in postMessage calls. I've added a test using bigints to verify these claims.

This update reduces the default worker size from 267,753 bytes to 213,648, a nice 20% reduction. Unfortunately I doubt we'll see much of an impact on the PowerSync SDK because the sync half of the worker still uses Uris.

Further, version 0.8.0 replaces the OPFS file system based on atomics and shared array buffer with a new implementation not requiring those (by lazily opening files when a database lock is acquired). This only affects Safari because we can use OPFS in shared workers on Firefox and readwrite-unsafe on Chrome, but this finally means OPFS is available in all major browsers without additional setup.

I've disabled the build_runner test step due to a bug in recent build_runner versions (linked from a comment).

[stevensJourney]

These are very nice improvements