Disable `devtools` for Release profile

File `src-tauri/Cargo.toml` enables `devtools`:
```
tauri = { version = "1.6.1", features = [
...
"devtools"
]}
```

We need `devtools` for having more information during testing, but it should be disabled for builds which we ship to the end-user.

Start with src-tauri/Cargo.toml and inspect how the Tauri features are configured for testing and release builds. Ensure shipped builds do not enable devtools while testing retains the additional information, then verify the relevant release configuration.

Written by the indexing model from the issue text.