chore(ci): push l1-contracts tests off of critical path (#6400)

I noticed that we've currently put running `forge test` on
`l1-contracts` on the critical path for CI such that e2e tests are
blocked by it. These take ~3 mins to complete so I think it makes sense
to run these in parallel.

I've then made a new earthly target to run these tests separately.

.github/workflows/ci.yml

@@ -333,6 +333,18 @@ jobs:
         timeout-minutes: 40
         run: earthly-ci --no-output ./+barretenberg-acir-tests-bb.js
 
+  l1-contracts-test:
+    needs: setup
+    runs-on: ${{ github.event.pull_request.user.login || github.actor }}-x86
+    steps:
+      - uses: actions/checkout@v4
+        with: { ref: "${{ env.GIT_COMMIT }}" }
+      - uses: ./.github/ci-setup-action
+        with:
+          concurrency_key: l1-contracts-${{ github.event.pull_request.user.login || github.actor }}-x86
+      - name: "Test l1 contracts"
+        run: earthly-ci --no-output ./l1-contracts+test
+
   docs-preview:
     needs: build
     runs-on: ${{ github.event.pull_request.user.login || github.actor }}-x86

l1-contracts/Earthfile

@@ -8,5 +8,10 @@ build:
     # "slither": "forge clean && forge build --build-info --skip '*/test/**' --force && slither . --checklist --ignore-compile --show-ignored-findings --config-file ./slither.config.json | tee slither_output.md",
     # "slither-has-diff": "./slither_has_diff.sh"
     RUN solhint --config ./.solhint.json --fix "src/**/*.sol"
-    RUN forge clean && forge fmt --check && forge build && forge test --no-match-contract UniswapPortalTest
-    SAVE ARTIFACT /usr/src/l1-contracts /usr/src/l1-contracts
+    RUN forge clean && forge fmt --check
+    RUN forge build
+    SAVE ARTIFACT /usr/src/l1-contracts /usr/src/l1-contracts
+
+test:
+    FROM +build
+    RUN forge test --no-match-contract UniswapPortalTest