Add lock file for sdk-harness test workspace, pin fuel-core to 0.17.3…

…, fix sdk-harness CI issues (FuelLabs#4248)

## Description

The lock file pins the fuel-core crates to 0.17.3, there appears to be
some breakage in 0.17.4:
https://github.com/FuelLabs/sway/actions/runs/4371254731/jobs/7646959456

I tried adding the sdk-harness test crates to the top-level workspace,
but this caused loads more unrelated errors which I'm not sure how to
address just yet. This PR should at least get CI working again for now.

Also adds the `--locked` flag to the sdk-harness `cargo test` invocation
in CI to avoid future unrelated breakage.

## Checklist

- [ ] I have linked to any relevant issues.
- [ ] I have commented my code, particularly in hard-to-understand
areas.
- [ ] I have updated the documentation where relevant (API docs, the
reference, and the Sway book).
- [ ] I have added tests that prove my fix is effective or that my
feature works.
- [x] I have added (or requested a maintainer to add) the necessary
`Breaking*` or `New Feature` labels where relevant.
- [x] I have done my best to ensure that my PR adheres to [the Fuel Labs
Code Review
Standards](https://github.com/FuelLabs/rfcs/blob/master/text/code-standards/external-contributors.md).
- [x] I have requested a review from the relevant team or maintainers.

.github/workflows/ci.yml

@@ -278,7 +278,7 @@ jobs:
       - name: Build All Tests
         run: cd test/src/sdk-harness && bash build.sh --locked && cd ../../../
       - name: Cargo Test sway-lib-std
-        run: cargo test --manifest-path ./test/src/sdk-harness/Cargo.toml -- --nocapture
+        run: cargo test --locked --manifest-path ./test/src/sdk-harness/Cargo.toml -- --nocapture
 
   forc-unit-tests:
     runs-on: ubuntu-latest

.gitignore

@@ -15,8 +15,3 @@ sway-lib-std/Forc.lock
 
 # Forc's build directory
 out
-
-# Don't lock example or lib-std test harnesses in order to try and catch
-# accidental upstream patch release breakage before users do.
-examples/*/Cargo.lock
-test/src/sdk-harness/Cargo.lock