Add packet.proto as a static_lib for Java lib
Add packet.proto as a static_lib for Java lib

static_lib ensures that the code is included as part of the library
whereas "libs" only includes that code as part of the classpath.

Bug: b/210138227
Test: CHQTS
Change-Id: Ibd1a995427fe186ff6216e7262c11f366230e9f9
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/78320
Reviewed-by: Wyatt Hepler <cca3bedb37979eacd157a9bceb473582df8aea1e@google.com>
Pigweed-Auto-Submit: Anthony Stange <3bebc424bf227777417531d2ddb8779ff751e32b@google.com>
Commit-Queue: Anthony Stange <3bebc424bf227777417531d2ddb8779ff751e32b@google.com>

google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed