ci: Remove unused Foundry cache steps (#431)

Summary
- drop the Foundry library and build artifact cache restores from the
e2e workflow
- also remove the Foundry build cache from the dedicated Foundry tests
workflow since it wasn’t providing value

Testing
- Not run (not requested)

.github/workflows/task-e2e.yml

@@ -118,23 +118,6 @@ jobs:
           key: ${{ runner.os }}-bun-${{ hashFiles('**/bun.lock') }}
           restore-keys: |
             ${{ runner.os }}-bun-
-      - name: Cache Foundry libraries
-        uses: actions/cache/restore@v4
-        with:
-          path: ../contracts/lib
-          key: ${{ runner.os }}-foundry-libs-${{ hashFiles('.gitmodules') }}
-          restore-keys: |
-            ${{ runner.os }}-foundry-libs-
-
-      - name: Cache Foundry build artifacts
-        uses: actions/cache/restore@v4
-        with:
-          path: |
-            ../contracts/out
-            ../contracts/cache
-          key: ${{ runner.os }}-foundry-build-${{ hashFiles('contracts/foundry.toml', 'contracts/**/*.sol') }}
-          restore-keys: |
-            ${{ runner.os }}-foundry-build-
       - uses: docker/login-action@v3
         with:
           registry: ghcr.io

.github/workflows/task-foundry-tests.yml

@@ -38,16 +38,6 @@ jobs:
         with:
           version: v1.4.3
 
-      - name: Cache Foundry build artifacts
-        uses: actions/cache@v4
-        with:
-          path: |
-            contracts/out
-            contracts/cache
-          key: ${{ runner.os }}-foundry-build-${{ hashFiles('contracts/foundry.toml', 'contracts/**/*.sol') }}
-          restore-keys: |
-            ${{ runner.os }}-foundry-build-
-
       - run: forge --version
       - run: forge fmt --check
       - run: forge build --sizes