Consume commons-net from Gerrit plugin API

Gerrit core now exposes commons-net via the plugin API classpath, so the
plugin no longer needs to declare it as an explicit dependency.

Remove the direct dependency on @commons-net//jar.

Also format the BUILD file with buildifier.

Depends-On: https://gerrit-review.googlesource.com/c/gerrit/+/558621
Change-Id: I69a8ab96f316ce0d27e9994a570ac75172b58b65

BUILD

diff --git a/BUILD b/BUILD
index 10896bf..3831c0f 100644
--- a/BUILD
+++ b/BUILD
@@ -54,10 +54,9 @@
     visibility = ["//visibility:public"],
     exports = PLUGIN_DEPS + PLUGIN_TEST_DEPS + [
         ":high-availability__plugin",
-        "@global-refdb//jar",
-        "@wiremock//jar",
-        "@jgroups//jar",
-        "@commons-net//jar",
         "@failsafe//jar",
+        "@global-refdb//jar",
+        "@jgroups//jar",
+        "@wiremock//jar",
     ],
 )