Bazel: Fix standalone build mode

Mockito dependency is already exposed in acceptance-framework and is
not needed.

Change-Id: I8eae00bb82f0c622056b737292fc97b55cca588a
diff --git a/BUILD b/BUILD
index 06a894a..c3d6504 100644
--- a/BUILD
+++ b/BUILD
@@ -41,6 +41,5 @@
     visibility = ["//visibility:public"],
     exports = PLUGIN_DEPS + PLUGIN_TEST_DEPS + [
         ":oauth__plugin",
-        "@mockito//jar",
     ],
 )