feat(core): improve config deserialization error messages

[lucasfernog]

What kind of change does this PR introduce?

• Bugfix
• Feature
• Docs
• New Binding issue #___
• Code style update
• Refactor
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change?

• Yes, and the changes were approved in issue #___
• No

Checklist

• When resolving issues, they are referenced in the PR's title (e.g fix: remove a typo, closes #___, #___)
• A change file is added if any packages will require a version bump due to this PR per the instructions in the readme.
• I have added a convincing reason for adding this feature, if necessary

Other information

[lucasfernog]

The error message now looks like this:

error: failed to run custom build command for `api v0.1.0 (/home/lucas/projects/tauri/tauri/examples/api/src-tauri)`

Caused by:
  process didn't exit successfully: `/home/lucas/projects/tauri/tauri/examples/api/src-tauri/target/debug/build/api-ff9354c88ae6ad14/build-script-build` (exit status: 1)
  --- stdout
  cargo:rerun-if-env-changed=TAURI_CONFIG
  cargo:rerun-if-changed=tauri.conf.json
  unknown field `$schemas`, expected one of `$schema`, `package`, `tauri`, `build`, `plugins`
  found an unknown configuration field. This usually means that you are using a CLI version that is newer than `tauri-build` and is incompatible. Please try updating the Rust crates by running `cargo update` in the Tauri app folder.
       Error failed to build app: failed to build app
error Command failed with exit code 1.

It is not a panic anymore and it prints the entire stdout/stderr.