Gradle wrapper security updates (microsoft#381)

* Add gradle-wrapper.jar checksum validation workflow.

* Add gradle wrapper distribution checksum values.

.github/workflows/gradle-wrapper-validation.yml

@@ -0,0 +1,14 @@
+# Check gradle-wrapper.jar checksums against official Gradle releases.
+# See: https://github.com/marketplace/actions/gradle-wrapper-validation
+# This workflow was copied from the link above.
+
+name: "Validate Gradle Wrapper"
+on: [push, pull_request]
+
+jobs:
+  validation:
+    name: "Validation"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: gradle/wrapper-validation-action@v1

java/gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
+distributionSha256Sum=f6b8596b10cce501591e92f229816aa4046424f3b24d771751b06779d58c8ec4
 distributionUrl=https\://services.gradle.org/distributions/gradle-7.5.1-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

java/src/test/android/gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Wed Oct 19 16:43:50 PDT 2022
 distributionBase=GRADLE_USER_HOME
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.4-bin.zip
 distributionPath=wrapper/dists
-zipStorePath=wrapper/dists
+distributionSha256Sum=8cc27038d5dbd815759851ba53e70cf62e481b87494cc97cfd97982ada5ba634
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.4-bin.zip
 zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists