Update main-build.yml (#1200)

Missed ./gradlew command.


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Author: Miqueasher

.github/workflows/main-build.yml

@@ -226,7 +226,7 @@ jobs:
         uses: gradle/actions/setup-gradle@ed408507eac070d1f99cc633dbcf757c94c7933a #v4.4.3
 
       - name: Build snapshot with Gradle
-        run: contractTests -PlocalDocker=true
+        run: ./gradlew contractTests -PlocalDocker=true
 
   application-signals-lambda-layer-build:
     runs-on: ubuntu-latest