do not prefix with artifacts if absolute path given

```
 nix run .#beaker -- wasm  store-code ./result/lib/cw_xc_gateway  --signer-mnemonic "$CI_COSMOS_MNEMONIC"
```

expands to 
```
artifacts./result/lib/cw_xc_gateway
```

expected
```
<Dir with Beaker.toml>/result/lib/cw_xc_gateway 
```