Eigrp: only compute metrics in the given mode

[dhalperi]

Fix #4051

[batfish-bot]

This change is 

[codecov]

Codecov Report

Merging #4065 into master will decrease coverage by <.01%.
The diff coverage is 83.33%.

@@             Coverage Diff              @@
##             master    #4065      +/-   ##
============================================
- Coverage     75.03%   75.02%   -0.01%     
+ Complexity    24498    24492       -6     
============================================
  Files          2023     2023              
  Lines         98252    98253       +1     
  Branches      11676    11679       +3     
============================================
- Hits          73720    73714       -6     
- Misses        19215    19219       +4     
- Partials       5317     5320       +3

Impacted Files	Coverage Δ	Complexity Δ
.../org/batfish/datamodel/eigrp/EigrpProcessMode.java	100% <ø> (ø)	1 <0> (ø)	⬇️
...in/java/org/batfish/datamodel/eigrp/EigrpEdge.java	60% <0%> (-1.54%)	11 <0> (ø)
.../java/org/batfish/datamodel/eigrp/EigrpMetric.java	91.76% <93.75%> (+1.17%)	25 <2> (-2)	⬇️
...rc/main/java/org/batfish/bddreachability/Edge.java	67.64% <0%> (-2.95%)	11% <0%> (-1%)
...java/org/batfish/datamodel/EigrpExternalRoute.java	75.47% <0%> (-1.89%)	12% <0%> (-1%)
...col/src/main/java/org/batfish/role/InferRoles.java	91.6% <0%> (-0.73%)	69% <0%> (ø)
...tfish/representation/cisco/CiscoConfiguration.java	83.92% <0%> (-0.13%)	531% <0%> (-1%)

[progwriter]

Reviewed 8 of 8 files at r1.
Reviewable status: complete! all files reviewed, all discussions resolved