Fixes bug in wasm-builder with cargo publish (#7299)

* Fixes bug in wasm-builder with cargo publish

There was a bug in wasm-builder which resulted in generating a
`Cargo.lock` in the project directory because of running `cargo
metadata`. This resulted in commands like `cargo publish` to fail (if
there was no `Cargo.lock` before building), because it checks that the
project directory isn't modified.

* Update utils/wasm-builder/src/wasm_project.rs

Co-authored-by: André Silva <[email protected]>

Co-authored-by: André Silva <[email protected]>