Clean up third_party imports in BUILD files

This removes the following unnecessary imports:

//third_party/java/activation
//third_party/java/bouncycastle
//third_party/java/bouncycastle_bcpg
//third_party/java/dagger
//third_party/java/dnsjava
//third_party/java/jaxws_api
//third_party/java/jcommander
//third_party/java/joda_money
//third_party/java/joda_time
//third_party/java/json_simple
//third_party/java/junit
//third_party/java/mockito
//third_party/java/re2j
//third_party/java/servlet/servlet_api
//third_party/java/truth:truth8

The exact command run to generate this CL was:

build_cleaner '//third_party/java_src/gtld/...' -c '' --dep_restrictions='//third_party/java/activation,//third_party/java/bouncycastle,//third_party/java/bouncycastle_bcpg,//third_party/java/dagger,//third_party/java/dnsjava,//third_party/java/jaxws_api,//third_party/java/jcommander,//third_party/java/joda_money,//third_party/java/joda_time,//third_party/java/json_simple,//third_party/java/junit,//third_party/java/mockito,//third_party/java/re2j,//third_party/java/servlet/servlet_api,//third_party/java/truth:truth8'

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=202344774

javatests/google/registry/module/backend/BUILD

@@ -18,10 +18,7 @@ java_library(
         "//java/google/registry/request",
         "//java/google/registry/util",
         "//javatests/google/registry/testing",
-        "@com_google_truth",
-        "@com_google_truth_extensions_truth_java8_extension",
         "@javax_servlet_api",
-        "@joda_time",
         "@junit",
         "@org_mockito_all",
     ],