use the "test" scope for the io.grpc:grpc-testing dependency (#858)

reduces runtime jar and removes unused classes from the distribution.

Author: votez

build.gradle

@@ -69,7 +69,6 @@ dependencies {
     compile group: 'com.auth0', name: 'java-jwt', version:'4.4.0'
     compile group: 'com.google.protobuf', name: 'protobuf-java', version: '3.21.9'
     compile group: 'com.google.api.grpc', name: 'proto-google-common-protos', version: '2.10.0'
-    compile group: 'io.grpc', name: 'grpc-testing', version: '1.54.2'
     compile group: 'com.google.protobuf', name: 'protobuf-java-util', version: '3.21.9'
     compile group: 'com.google.oauth-client', name: 'google-oauth-client', version: '1.35.0'
     compile group: 'com.google.http-client', name: 'google-http-client-gson', version: '1.19.0'
@@ -83,6 +82,7 @@ dependencies {
     testCompile group: 'junit', name: 'junit', version: '4.12'
     testCompile group: 'com.googlecode.junit-toolbox', name: 'junit-toolbox', version: '2.4'
     testCompile group: 'ch.qos.logback', name: 'logback-classic', version: '1.2.3'
+    testCompile group: 'io.grpc', name: 'grpc-testing', version: '1.54.2'
     testImplementation 'io.opentracing:opentracing-mock:0.33.0'
 }