Adding unit tests for Transport Actions

[saratvemulapalli]

*Issue #195 *

Description of changes:
Taking first stab at adding unit tests for newly added Transport Actions

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov]

Codecov Report

Merging #327 (4e6f4e8) into master (c25e630) will increase coverage by 1.40%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master     #327      +/-   ##
============================================
+ Coverage     72.95%   74.35%   +1.40%     
- Complexity     2003     2022      +19     
============================================
  Files           201      201              
  Lines          9563     9563              
  Branches        852      852              
============================================
+ Hits           6977     7111     +134     
+ Misses         2173     2022     -151     
- Partials        413      430      +17     

Flag	Coverage Δ	Complexity Δ
cli	79.27% <ø> (ø)	0.00 <ø> (ø)
plugin	73.95% <ø> (+1.51%)	0.00 <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ	Complexity Δ
...port/SearchAnomalyDetectorInfoTransportAction.java	54.54% <0.00%> (-9.10%)	4.00% <0.00%> (ø%)
...asticsearch/ad/cluster/ADClusterEventListener.java	90.00% <0.00%> (-4.00%)	14.00% <0.00%> (-1.00%)
...sticsearch/ad/indices/AnomalyDetectionIndices.java	49.01% <0.00%> (-0.33%)	39.00% <0.00%> (-1.00%)
...ransport/DeleteAnomalyDetectorTransportAction.java	60.25% <0.00%> (+3.84%)	15.00% <0.00%> (+1.00%)
...search/ad/transport/GetAnomalyDetectorRequest.java	100.00% <0.00%> (+15.38%)	13.00% <0.00%> (+3.00%)
...distroforelasticsearch/ad/model/EntityProfile.java	51.02% <0.00%> (+15.64%)	8.00% <0.00%> (+3.00%)
...arch/ad/transport/IndexAnomalyDetectorRequest.java	100.00% <0.00%> (+53.19%)	14.00% <0.00%> (+3.00%)
...earch/ad/transport/GetAnomalyDetectorResponse.java	75.36% <0.00%> (+75.36%)	7.00% <0.00%> (+7.00%)
...rch/ad/transport/IndexAnomalyDetectorResponse.java	100.00% <0.00%> (+100.00%)	5.00% <0.00%> (+5.00%)