Add missing license to test-utils crate

[h7kanna]

What was changed

Added license to test-utils crate to 'cargo-deny' failures

Why?

Checklist

1. Closes

2. How was this tested:

3. Any docs updates needed?

[cretz]

Can we instead have all just refer to the license at the root?

[h7kanna]

Yes with license = { workspace = true }

[cretz]

@Sushisource - is it ok if we do that in each crate and remove all the LICENSE.txt files but the one in the root? Also, can we remove the unnecessary opening line on the root LICENSE.txt? It seems to be preventing GitHub from recognizing it's MIT for repo-metadata purposes.

[Sushisource]

Sure, we can use one shared one and get rid of the line at the top.

[h7kanna]

Ok, made the required changes

[Sushisource]

Awesome! Thanks!