fix: revert gradle version used for generated assembly packages (bazel rules)

The new 7.x verison of gradle is incompatible with the used gradle build scripts format.

Author: vam-google

rules_java_gapic/resources/gradle/gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.10.3-bin.zip