Frr: Do not call addNeighbor on peer group neighbors

[ratulm]

Downstream code generates spurious warnings when addNeighbor is called for peerGroup neighbors.

[batfish-bot]

This change is 

[codecov]

Codecov Report

Merging #8157 (b33961c) into master (cd98766) will decrease coverage by 0.00%.
The diff coverage is 50.00%.

@@             Coverage Diff              @@
##             master    #8157      +/-   ##
============================================
- Coverage     74.49%   74.48%   -0.01%     
+ Complexity    43366    43363       -3     
============================================
  Files          3376     3376              
  Lines        169538   169538              
  Branches      20295    20295              
============================================
- Hits         126295   126283      -12     
- Misses        33556    33566      +10     
- Partials       9687     9689       +2     

Impacted Files	Coverage Δ
...org/batfish/representation/frr/FrrConversions.java	88.53% <50.00%> (-0.24%)	⬇️
...fish/bddreachability/BDDLoopDetectionAnalysis.java	80.23% <0.00%> (-2.33%)	⬇️
...src/main/java/org/batfish/coordinator/PoolMgr.java	59.52% <0.00%> (-1.20%)	⬇️
...batfish/src/main/java/org/batfish/main/Driver.java	48.00% <0.00%> (-0.45%)	⬇️
...java/org/batfish/dataplane/ibdp/VirtualRouter.java	87.56% <0.00%> (-0.25%)	⬇️
...ain/java/org/batfish/storage/FileBasedStorage.java	86.08% <0.00%> (-0.25%)	⬇️
...src/main/java/org/batfish/coordinator/WorkMgr.java	75.74% <0.00%> (-0.16%)	⬇️

[dhalperi]

Reviewed 1 of 1 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @ratulm)