feat: improve integrationtests workflow caching (#2551)

- Add pnpm cache step using actions/cache@v4 for node_modules and pnpm store
- Remove redundant pnpm cache from setup-node step
- Add plugin dist cache to prevent unnecessary rebuilds

Similar to the caching strategy in smoke-tests.yml, this change should
significantly reduce workflow execution time by caching both dependencies
and build artifacts.

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: Sayo <[email protected]>

.github/workflows/integrationTests.yaml

@@ -15,14 +15,30 @@ jobs:
         steps:
             - uses: actions/checkout@v4
 
+            - name: Cache pnpm
+              uses: actions/cache@v4
+              with:
+                  path: |
+                      ~/.pnpm-store
+                      **/node_modules
+                  key: ${{ runner.os }}-pnpm-${{ hashFiles('**/pnpm-lock.yaml') }}
+                  restore-keys: ${{ runner.os }}-pnpm-
+
+            - name: Cache plugin dist
+              uses: actions/cache@v4
+              with:
+                  path: |
+                      **/packages/plugin-*/dist
+                  key: ${{ runner.os }}-plugin-dist-${{ hashFiles('**/pnpm-lock.yaml') }}
+                  restore-keys: ${{ runner.os }}-plugin-dist-
+
             - uses: pnpm/action-setup@v3
               with:
                   version: 9.15.0
 
             - uses: actions/setup-node@v4
               with:
                   node-version: "23.3.0"
-                  cache: "pnpm"
 
             - name: Clean up
               run: pnpm clean