Show Dart file locations in the stacktraces for errors

[elliette]

Fixes #7392

This PR:

• Includes source maps for dart2js and dart2wasm builds of DevTools
• When reporting an error to the user and Google Analytics, uses the mapped stack trace instead of the minified stack trace
• Programmatically determines whether to use the JS source map or wasm source map based on whether the wasm experiment is enabled

dart2js mapped stacktrace:

dart2wasm mapped stacktrace:

[elliette]

This is the latest candidate in g3. It contains flutter/flutter#155846 which is required so that we can pull in the latest version of package:stack_trace

[kenzieschmoll]

Awesome thank you for working on this! Would be a bonus at some point if some of this logic could get upstreamed into a dart package so all Flutter web apps could have an easy way to handle source mapping.