R4R: Don't serialize Account Number and Sequence Number in signatures

[ValarDragon]

This was not needed to be included within the tx body, as its in the
state.
Closes #2952

• Targeted PR against correct branch (see CONTRIBUTING.md)

• Linked to github-issue with discussion and accepted design OR link to spec that describes this work.

• Wrote tests - existing tests suffoce

• Updated relevant documentation (docs/) - auth spec doesn't exist yet

• Added entries in PENDING.md with issue #

• rereviewed Files changed in the github PR explorer

---

For Admin Use:

• Added appropriate labels to PR (ex. wip, ready-for-review, docs)
• Reviewers Assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[ValarDragon]

Previously the benchmark masked the true tx size, since it omitted account number, sequence number, and gas (as they were the default value). This increase is due to gas, but removal of accnum and sequence number will increase space savings.

[codecov]

Codecov Report

Merging #2977 into develop will decrease coverage by 0.05%.
The diff coverage is 78.57%.

@@             Coverage Diff             @@
##           develop    #2977      +/-   ##
===========================================
- Coverage    56.29%   56.24%   -0.06%     
===========================================
  Files          120      120              
  Lines         8406     8387      -19     
===========================================
- Hits          4732     4717      -15     
+ Misses        3352     3348       -4     
  Partials       322      322

[alexanderbez]

LGTM. Thanks for the note ExampleTxSendSize, although I'm still not quite sure why it's a few bytes extra?

[cwgoes]

Let's add back the testcase? Otherwise LGTM.

[ValarDragon]

Hope this clears up the situation bez: Before gas was 0, so it was being omitted as thats the protobuf default value. I went ahead and changed it to be non-zero so that it would show up in the total size. There were no bytes removed from that test, since that test didn't account for size of account number or sequence number to begin with. (They were both 0), I adapted the test locally to confirm that space was saved if it did account for them previously.