fix(sync): Slightly increase some syncer defaults

[teor2345]

Motivation

We changed the syncer defaults to make full verification more reliable, but that slowed down syncing by about 15%.

This is a partial revert of PR #4670.

Solution

• Increase the syncer defaults to about halfway between the previous and current defaults

This is a temporary fix until we get orchard batch verification.

Review

This PR needs a full sync test before it gets merged.

Reviewer Checklist

• Full sync is greater than 85% at 6 hours

[teor2345]

I'm running a full sync here:
https://github.com/ZcashFoundation/zebra/actions/runs/2546930195

We want it to get higher than 85% at 6 hours.

[codecov]

Codecov Report

Merging #4679 (023479b) into main (c75a68e) will increase coverage by 0.11%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #4679      +/-   ##
==========================================
+ Coverage   78.81%   78.93%   +0.11%     
==========================================
  Files         304      304              
  Lines       37509    37509              
==========================================
+ Hits        29564    29606      +42     
+ Misses       7945     7903      -42     

[conradoplg]

It timed out at 96.781%, so it seems good?

[teor2345]

It timed out at 96.781%, so it seems good?

Yep that's much better, we'll fix the timeout with #4661

[gustavovalverde]

This is working as expected (sync is faster in the tested workflow). As it's a very straightforward change I'll approve it so we can test PRs being dependent on this one.